GB2493548A - Rotating cube puzzle - Google Patents

Abstract

A manipulative puzzle having the external appearance of a 2x2x2 cube 10 comprises a core (fig. 10), a fixed piece 12 in fixed rotational position relative to the core, and seven pieces 14 rotatable in groups of four relative to the core. The fixed piece is spaced from the core, is able to slide towards and away from the core, and is biased by resilient means towards the core and rotatable pieces. The resilient means is preferably a coil spring (66, fig. 10) which forms part of an arrangement for mounting the fixed piece to the core. The moveable pieces are preferably supported on the core by support plates extending from the core (fig. 7), the support pieces defining gaps and the moveable pieces having hooks which fit into the gaps and locate behind the plates. The core is preferably formed of several components secured together, for example using a screw (fig. 10). The fixed and moveable pieces define individual cubes forming the 2x2x2 cube, and the arrangement allows groups of four individual cubes to be rotated around three orthogonal axes, with the sliding movement of the fixed piece assisting smooth movement of the pieces.

Description

SPATIAL LOGIC PUZZLE

FIELD OF THE INVENTION

The present invention relates to a spatial logic puzzle which is useful as a plaything and/or to teach spatial awareness and a systematic approach to problem solving, and in particular to an improved mechanism for operation of such a puzzle..

BACKGROUND TO THE INVENTION

Professor Erno Rubik is the inventor of the well-known Rubik's cube described inHlJ-B-]70062 (1976), see also IJS-A-4378116. It is based on the idea of providing a body made up from one or more sets of equivalent but identifiable pieces which are interconnected so that groups of pieces are relatively rotatable about three orthogonal axes. The pieces can exchange positions while the cxtemal shape of the body remains unchanged. Solutions of the puzzle are disclosed in a book by Tom Wemeck, "Der Zauber-Wurfel", Wilhelm 1-leyne Verlag, 1981 (ISBN 3453-41449-7), the disclosure of which is incorporated herein by reference. Although the most popular form of the puzzle was a 3 x 3 x 3 cube, it was also produced as a 2 x 2 x 2 and 4 x 4 x 4 cube.

A mechanism for a 2 x 2 x 2 cube is disclosed in JP-A-53-l 13642 (Terutoshi, also JP-B-55-8193). The drawings show a solid spherical core to which are screw-attached relatively small guide plates having spherical inner and outer surfaces concentric with the surface of the core. Movable cubes have inner part spherical surfaces supported by the guide plates, posts extending from the inner surfaces and part spherical plates at the ends of the posts that fit slidcably behind the guide plates by which they are retained. That mechanism is criticised by Professor Rubik in US-A- 4378117 on the grounds that it does not ensure smooth and accurate movement of the movable cubes, the plates can become deformed and the life of the mechanism is limited.

A further mechanism for a 2 x 2 x 2 cube is described in US 4344623 (Isobe). A spherical apparently solid central support has one of the cubes fixed to it and carries six guide plates disposed in an array about the support. Each guide plate is spaced a short distance above the spherical surface of the support and each has inner and outer part spherical curved faces corresponding to the curvature of the support. The guide plates are generally square when viewed in exterior elevation with corner cut-outs to allow the movable blocks or cubes to be fitted to the core. The guide plates are spaced laterally apart from one another such that the spaces between the edges of adjacent guide plates define guide tracks. The remaining seven blocks arc movable and have part spherical inner surfaces that conform to and can move over the exterior surfaces of the guide plates. Each movable block is formed in its inner face with a leg that fits into a track between adjacent guide plates and terminates in a retaining stud that fits between the spherical surface of the support and the inner spherical surfaces of the adjacent guide plates, the inner and outer surfaces of the stud being curved to conform to the central support and to the inner surfaces of the guide plates. No spring mechanism is provided for and although the mechanism is stated to provide smooth movement as well as easy assembly, in fact the tightness or slackness of the puzzle and hence its handling properties are set by manufacturing tolerances. US 4405131 (Hovarth; see also 4540177) is similar and is based on an inner core member, a plurality of mutually spaced retainer members connected to and spaced from and surrounding said core member and having inside faces lying in a spherical plane concentric with said core member, a plurality of peripherally spaced slide members underlying said retainer member inside faces and each being movable in circular paths about orthogonally related axes intersecting at the centre of said spherical plane, a face member connected to each of said slide members and disposed outwardly of said slide and retainer members including one interlocking member having a plurality of rib elements in locking engagement with three of said retainer members and a plurality of tongue elements in releasable locking engagement with three of said slide members; and a face member connected to said interlocking member. Again the tightness or slackness of the puzzle is set by manufacturing tolerances and there is no provision for spring control of the puzzle tightness. Essentially the same mechanism is disclosed in US 7306225 (Lu) but with a spider core, an object of the disclosed construction being the avoidance of springs.

The disclosure of JP-B-55-008313 (Terutoshi) is similar and also employs a central support in the form of a ball carrying six concentric pail spherical guide members disposed in pairs along the three orthogonal axes and spaced a small distance above the surface of the ball. The attachment of the guide members to the central ball is by screws. Gaps are defined between adjacent pairs of follower plates. The movable pieces each have a part spherical plate which is trapped between the surface of the ball and a pair of the guide plates. Each movable piece is connected to its trapped plate by a single peg which passes through the gap between the side plates. Because the piece is supported from the single peg, thick sections are needed where the piece and the peg join if adequate support and rigidity is to be achieved.

A somewhat similar mechanism is employed in a 4 x 4 x 4 cube, see US 4421311 (Sebesteny) and in a commercially produced embodiment ("Rubik's Revenge") employs eight guide plates each being a spherical triangle occupying substantially a quadrant and trapped between and supported in closely spaced relationship above a three-part spherical core. However, assembly of the core involves a number of fixing screws and correct tightness of the puzzle depends on manufacturing tolerances because there is no provision for a spring or springs to be incorporated to maintain correct tightness.

US43Th1 17 (Rubik) discloses an arrangement for a 2 x 2 x 2 puzzle in which resilient pivots are built into the cube mechanism which give rise to identical and controllable frictional forces between spherical surfaces being displaced on each other, the puzzle has its moveable pieces assembled without clearance between them and with a continuous joint and the useful life of the puzzle is unlimited. The puzzle is based on shaped interlocking pieces and is held together by hollow studs having screws and coil springs on the screws. The above mechanism is criticised in US-A-7306225 on the ground that the spring arm construction employed make it difficult to fit the pieces to the core, and in particular that it is very difficult to fit the last piece to the core.

A frirther mechanism based on shaped interlocking pieces is disclosed in US-A- 7306225 (Lu). It has no intemal spring mechanism to control the frictional forces between the pieces.

Commercially available 2 x 2 x2 Rubiks cubes have a castellated spider mechanism based on a six-armed spider relative to which one piece is mechanically located in a fixed position and the remaining pieces are movable. Castellated members fit on the arms of the spider and each fit within two of the pieces. Three of the castellated members are rotatable on their respective arms and three of them are fixed.

The mechanism has the feature that the puzzle can be assembled simply by inter-engaging the individu& internal parts and pieces and pushing the last piece into place, no screws or springs being used, see US 6210723 (Kremer). However, in such structures there is no spring to accommodate manufacturing tolerances and take up any slack.

SUMMARY OF THE INVENTION

In some embodiments there is provided a manipulative puzzle in the form of a 2 x 2 x 2 cube having a core supporting one piece in fixed position relative to the core and seven pieces that are rotatable in groups of four relative to the core, wherein the fixed piece is supported for sliding movement radially of the core and is positioned at a small spacing from the core, resilient means biasing the fixed piece towards the movable pieces for establishing the tightness of the puzzle. Contact with the movable pieces compresses the spring so that the fixed cube "floats" on the resilient means (e.g. a metal wire coil spring), is urged into contact with the movable pieces and the three of the resilient means rather than manufacturing tolerances establishes the tightness of the puzzle and the frictional resistance to cube rotation. For the above reasons embodiments of the present puzzle may give faster and smoother spin than embodiments not incorporating resilient means and may be more forgiving to misalignment since movement of the fixed cube within a range of travel and under the control of the resilient means permits the puzzle to flex open slightly and facilitates rotation.

In some embodiments of the above puzzle the core may be formed with a socket in which said one piece is non-rotatably received, a post extending from said one piece into the core and said resilient means being in compression between said one piece and the post for biasing said one piece towards the core. Said one piece in some embodiments comprises inner and outer portions for fastening together during assemNy of the puzzle, the inner portion having a tubular hub providing a route for insertion of the post through it and into the core. The resilient means may be a coil spring on the post. In some embodiments the post extends through the core and is secured to it by a fixing member e.g. a screw or a rivet at an end remote from the fixed cube. At least one rotatable piece may comprise inner and outer portions for fastening together during assembly of the puzzle, the inner portion having a tubular hub providing a route for insertion of the fixing member through it and into the post. The core may be partly or mainly hollow and may be formed as a plurality of components e.g. three components and the post may pass to or through each of them. Guide plates for the movable pieces may be supported by and held in fixed position between components of the core Further embodiments provide a manipulative puzzle comprising eight interconnected pieces in a 2 x 2 x 2 cube and having three orthogonal planes in which groups of four pieces can be rotated to exchange relative positions, said puzzle comprising a body, one piece supported in fixed rotational position relative to the body and seven pieces supported for rotational movement relative to the body, wherein said one piece is supported at a spacing from the body for sliding movement towards and away from the body and resilient means biases said one piece towards the body and towards contact with the slideable pieces.

In further embodiments there is provided a manipulative puzzle comprising eight interconnected pieces in a 2 x 2 x 2 cube and having three orthogonal planes in which groups of four cubes can be rotated to exchange relative positions, said puzzle comprising: a body; a piece supported by the body in fixed position relative thereto; seven support plates carried by the body and having the outline of spherical triangles occupying an octant of a circle with gaps between the plates adjacent the division planes for piece rotation; and seven pieces moveable relative to said body, slidcably supported on the support plates and connected thereto by hook formations at their vertices that fit into said gaps and locate bchind said plates.

In embodiments the body comprises at least two components and a plurality of the support plates have connector formations that fit between the components for supporting the plates in fixed position relative to the body. For example the body may comprise first, second and third components. A first group of three support plates may have connector formations that fit between the first and second body components and a second group of three components may have connector formations that fit between the second and third body components. To facilitate rotation the support plates of the first group may have arcuate formations at vertices furthest from the fixed piece for receiving adjacent hook formations of a group of pieces to be rotated, the adjacent hook formations together defining an axle and the appropriate one of the arcuate formations defining a bearing for the axle. The support plates of said plurality may have connector formations on interior faces thereof defined by posts of non-circular profile that fit through corresponding apertures defined by adjacent components of the core and by feet that fit into sockets in the components, and the feet may have first and second ends that fit into respective sockets in the adjacent components. The posts arc conveniently of generally triangular profile. For receiving the inner component of the fixed piece, the first body component may be formed with a three-sided socket into which the fixed piece fits. In embodiments the seventh support plate has on its interior face a connector formation in the form of a non-circular post that locates into a corresponding socket in the third body component, in further cmbodimcnts the post and socket being of generally triangular profile.

The core components may be secured together by a post having a first end located within the fixed piece, passing through the body and having a second end within a p[eee position in a layer of pieces not including the fixed piece and diagonally opposite to the fixed piece. The pieces may be formed with inner and outer components, the ilmer components being formed with tubular hubs giving access to the first and second ends of the posts. The core components may be secured together by a fixing screw passed through the hub of the inner piece component at the position diagonally opposed to the fixed piece and into the second end of the post. The pieces may comprise three-sided inner components and three-sided outer components welded to them. The faces of the outer components may be individually coloured or marked or may be shaped together to form a design e.g. of a human, animal or toy figure.

In a yet flirther embodiment the invention provides a manipulative puzzle comprising interconnected pieces in a cubical arrangement and having three orthogonal planes in which groups of pieces can be rotated to exchange relative positions, said puzzle comprising: a body; support plates carried by the body and having the outline of spherical triangles occupying an octant of a circle with gaps between the plates adjacent the division planes for piece rotation; and pieces moveable relative to said body, slideably supported on the support plates and connected thereto by formations that slide within and locate behind the gaps; wherein the body comprises a plurality of components between which formations on the support plates are trapped, and a post extends through the body with a fixing screw at at least one of its ends for securing the body components together. The puzzle may be a 2 x 2 x 2 puzzle or a 4 x 4 x 4 puzzle.

Embodiments of the invention provide simplified assembly and a reduced component count, which facilitates reliability in the manufacturing process and a reduction in the rate of rejects.

The various preferred or exemplified features of the embodiments described above may, of course, be used in association with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

How the invention may be put into effect will now be described by way of example only with reference to the accompanying drawings, in which: Fig. I is a trimetric view of a 2 x 2 x 2 cube puzzle; Fig. 2a is a perspective view of an inner component of an individual movable cube forming part of the puzzle of Fig. I showing a face thereof which is closer to a core of the puzzle; Fig 2b is a view of the inner component of Fig 2a but showing a face which is further from the core of the puzzle; Fig. 3 is a perspective view of four abutting inner components of movable cubes showing the faces thereof which are closer to the core of the puzzle; Fig 4 is a perspective view a fixed cube and guide plates showing the spatial relationships between them; Fig 5 is a view like Fig 4 but with the fixed cube and guide plates in a rotational position such that that one of the division planes of the puzzle coincides with the viewing direction; Fig. 6 is a further view of the fixed cube and guide plates in a rotational position such that a division plane continues to coincide with the viewing direction and a pivot point for four rotatable cubes coincides with the viewing direction; Fig 7 is a view of the guide plates centred on a guide plate located at an opposite corner from the fixed cube; Fig. 8 is a perspective view of the fixed cube and of normally concealed faces of two movable cubes with their supporting guide plates; Fig. 9 is a perspective view of an inner post and a spring carried by that post; Fig. 10 is an exploded view of the inner post, a fixed cube inner component, a three part core, a guide p'ate carried at the end of the inner post and a fixing screw; Fig. 11 is a view of the inner post, the fixed cube inner component, the adjacent core component and the guide plate carried at the end of the inner post, and Figs 12-15 arc similar views with additional components ofthc cube; Figs 16-21 are perspective views of the cube showing successive assembly states, the viewing directions being such that in Figs 16 -19 an internal post, when it is displayed, is in side view and in Figs 20 and 21 the viewing direction being rotated so that the post appears in end view, and Fig. 22 is an exploded view of the cube showing the components thereof

DESCRIPTION OF PREFERRED EMBODIMENT

In Fig. I there is shown a 2 x 2 x 2 movable cube or other piece puzzle 10 having a fixed cube 12 and seven movable cube positions 14a-14g, the cubes occupying those positions bcing rotatable in groups of four about three orthogonal division planes 11 a, 1 lb and 1 ic. As is conventional in puzzles of this type, the components of the cube are of injection-moulded plastics material e.g. ABS.

A mechanism for the puzzle has to provide appropriate movements for each of the different movable cube positions. Three of the cubes in positions corresponding to 14a, 14c and 14g abut the three internal faces 20a, 20b and 20c of the fixed cube. Cubes at these positions have only a single degree of freedom insofar as they can be rotated in that one of the division planes 11 a -lie corresponding to the internal faces that are in abutment but because of that abutment are prevented from rotation in either of the other two division planes. A second group of three cubes 14b, 14d, 14f can form part of a group of four coplanar cubes 12, 14a, 14b, 14c; 12, 14c, 14f, 14g; or 12, 14a. 14d, 14g which includes the fixed cube 12. The cubes of this group have two degrees of freedom and are free to rotate relative to the fixed cube 12 about division planes normal to the plane of the group but not in the division plane which is parallel to the group. For example the cube 14f is free to rotate relative to the cube 12 in division plane I Ia or lIb but not in plane lie and the cube 14d can rotate in the planes lib and lie but not in division plane Ha. The cube 14e which is diagonally opposed to and furthest from the fixed cube 12 has three degrees of freedom and relative rotation in all three division planes 1 Ia -1 Ic is possible. Indeed, rotation of any group of four cubes will involve rotation of the cube at position 14e. As will be described below, support plates for the illustrated movable cube positions are configured to accommodate the range of movements proper to those positions.

The puzzle has a three-part generally spherical core 72, 74, 76 (Figs. 10, 17-22) which fits onto a post 60 that extends diagonally across the puzzle from the underside of fixed cube 12 to the underside of movable cube position 14e. In addition to the fixed cube 12, the core provides support for seven guide plates 35, 37, 39 which underlie the seven movable cube positions, the guide plates together defining spherical inner and outer surfaces spaced a short distance above the spherical outer surface of the core and with channels between them corresponding to the rotational planes Ila -lie. The guide plate 39 fits under movable cube position 14e and is formed with a hole 40 through which a fixing screw 68 passes for threaded engagement into an end of the post to hold the components of the puzzle together. Each cube is formed with an ilmer half-cubical component which in the ease of the fixed cube 12 is a locator held in fixed positional relationship to the core (although as will be described below it can slide diagonally a limited distance on the post 60 under spring control) and in the case of the seven movable cubes 14a-14g are sliders that run on the guide plates 35, 37, 39. For that purpose each slider of a movable cube has at three of its vertices hooks defined by inwardly-facing posts 26 terminating in reverse-facing pads 28. As seen e.g. in Fig 8, the hooks clip onto the guide plates with the posts 26 fitting into the channels defined between the guide plates 35. 35 and with the pads 28 fitting against the inner faces of the guide plates to retain the sliders in place for movement over the inner faces of the guide plates as the cubes are rotated.

As previously explained the movable cubes are rotatable in groups of four and the inner components or sliders ofone such group 14e-14g appear in Fig 3. The sliders have four adloining vertices at which posts 26 formed with quarter-cylindrical outer surfaces 30 combine to form a pivot shaft and the pads 28a -28d combine to form a retaining stud that fits behind the guide plates 35, 37, 39. The remaining eight vertices have posts 26 and pads 28e -281 located adjacent the surfaces 20a. Those surfaces butt against corresponding surfaces of the other group of four cubes to define a division plane 1 la, 1 lb or lie. The pads 38 fit behind the guide plates 35, 37, 39 where they arc slideably retained. The result is that the group of cubes has a well-defined pivot axis and is stabilised at eight circumferential positions by the posts and pads 28e-281.

Correspondingly the guide plates have four adjacent corners which together define bearings 45 for the pivot shaft and have edges lying in a common plane for engagement with the posts 26 and pads 28e-28l, the edges forming a circumference of a circle interrupted by gaps adjacent the division planes for cube rotation. As a result the group of four cubes is freely rotatable and is supported in a stable attitude relative to the underlying guide plates, yawing and jamming being prevented. It will be appreciated that the role of the posts and pads as pivots and circumferential stabilisers is interchangeable depending on which group of four cubes is user-selected for rotation.

The guide plates and additionally the fixed cube together define three pivot bearings 45, one for each face of the cube that is rotatable relative to the fixed cube 12. It should be mentioned that the cube 12 is "fixed" only in relation to the core. To a person attempting to solve the puzzle its behaviour appears no different to that of the movable cubes 14a-12g.

As previously explained Figs 2a and 2b show an inner portion or slider of a moveable cube 14d. It has a tubular hub 15 open at both ends. Three fins 17a, 17b, 17c arise from the hub and are spaced 1200 apart. They terminate at three lateral walls 20a, 20b and 20c that are normally concealed within the cube and which cooperate with corresponding walls of the fixed cube 12 and with those of other movable cubes to define the rotational planes 11 a -lie. Inner edges 24 of the walls 20a -20c are curved so as to fit onto and slide over the guide plates 35, 37, 39 and both the inner end of the hub 15 and the inner edges 22 of the walls are correspondingly curved to fit onto and slide over the guide plates. Three inwardly facing posts 26 arise from the vertices of the inner portion and have quarter-cylindrical outer surfaces and quarter-cylindrical inner surfaces 30 which as previously explained can cooperate with corresponding surfaces of adjacent posts to provide a pivot. The posts 26 terminate at in-turned pads 28 of quarter-circLe profile, with the straight sides in the same plane as the outer surfaces of the walls 20a -20e and with a third side of arcuate shape facing towards hub 15. Outer portions of the cubes define the three exposed and coloured or otherwise marked or configured faces and are provided by three-sided covers 102 (Fig 16) which are glued or welded to the inner portions. Six of the movable cubes 14a -14d, 14f-14g can be provided with their covers pre-fitted but in this embodiment the covers for the fixed cube 12 and for the diagonally opposite movable cube 14e (as it is at the time of cube assembly) are glued or welded in place during assembly of the cube. After assembly of its inner component to the post and spring, the cover may be glued or welded in place with the fixed cube also then being pre-assembled.

The seven guide plates are each formed as spherical triangles each generally having the extent of an octant of a sphere. They fall into two groups of three with the plates within each group having the same shape and with a seventh plate whose shape is different from the others. As seen in Figs 4 and 5, a first group of plates 35 is closest to the fixed cube 12. It has its edge 47a closest to the fixed cube 12 spaced apart therefrom to permit rotation of a group of four cubes in a division plane parallel to the surface 20c as shown or in the case of the other two plates 35 the surfaces 20a and 20b. Its other two edges 47b, 47e are aligned with the division plane since in the other two division planes no rotation from the positions 14a, 14c, 14g defined by the plates 35 is possible.

It will be appreciated that where one group of cubes is to be rotated relative to the other, there has to be space for the side of the moving cubes and their hooks to pass whereas no such space is needed for the non-rotating group of cubes. For that reason, as is apparent in Figs. 5-6 and 18-19, the gaps permitting relative cube rotation appear offset to that side of the division plane where rotation of a group of cubes is provided for.

Each of the first group plates 35 has an arcuate cut-out 41 in its vertex facing away from the fixed cube 12 to define with adjacent vertices of plates 37, 39 a bearing for the axle defined by the four hook surfaces 30 described above. A second group of plates 37 is further from the fixed cube 11 and corresponds to positions 14b, 14d, 14 Each of them has two of its sides 49a, 49b that face away from the seventh plate 39 spaced apart from the division planes and from the corresponding sides 47c, 47b of the adjacent plates 37 to permit rotation and its third side 49c facing the seventh plate 39 coinciding with its division plane because rotation of a group of cubes in that plane is not possible.

The seventh support plate 39 as best seen in Fig 7 has each of its three edges spaced apart from the division plane in which it would otherwise lie since the movable cube in position 14e supported by plate 39 can and indeed must participate in rotation in all three division planes. The apertures through the plates 35 and 37 serve no purpose in the flmctioning of the puzzle, but are introduced to facilitate injection molding.

As seen in Fig. 8, the inner face of each support plate of the groups 35, 37 is formed with an inwardly facing post 52 of non-circular (in this embodiment triangular) section which extends into the core of the puzzle and terminates at a foot 50 having connector formations 54, 56 at its ends for fitting into sockets formed within the pieces of the core so that the core can provide firm and stable support for each of the support plates in a fixed and stable attitude. The connector formations 54, 25 differ in dimensions, shape or both as do the sockets 88, 92 (Fig. 10) in the core so that each support plate can be assembled to the core only in the intended attitude and not in the reverse attitude.

Fig. 9 shows a post which fits internally within the cube, extends between the fixed cube 12 and the diagonally opposite movable cube position 14e, holds the fixed cube to the core, provides support for the core components 72, 74, 76, provides support for the seventh support plate 39 and has a threaded end region to receive fixing screw 68 which holds the components of the cube together. A coil spring 66 fits onto to the shaft of the post 60 where it is retained by end cap 62. As is apparent from Fig. 10, inner component 70 of the fixed cube has an open-ended tubular hub that fits onto shaft with fins 17a, 17b, 17c fitting slideably through slots 64 in end cap 62 so that relative rotation of the post 60 and inner component 70 is prevented. The end cap 62 of post 60, however, is trapped behind the end of the hub, into which it cannot pass. First core cap component 72 has a part spherical region facing away from the fixed cube and a tubular region 78 facing towards the fixed cube into whose hub it fits with splines 80 (three in this embodiment) slideably received in hub sockets ISa, 15b, 15c of the fixed cube inner component 70 SO that relative rotation between the component 70 and the inner core 72 is prevented. The body of the first component is formed on its outer face with socket 82 of triangular profile into which the fixed cube inner component fits.

Central core component 74 is formed with a central transversely extending plate having a central aperture for fitting onto post 60 and with sockets 86 opening to the face which is visible in Fig. 10 for receiving connector formations 54 of the support plates 35 of the first group and sockets 88 opening to the face which is concealed in Fig. 10 for receiving connector formations 54 of the support plates 37 of the second group. The wall of the first core cap component 72 is formed at its rim with cut-outs 84 which face corresponding cut-outs in the wall the central component 74 so that when thesc two components fit together openings of triangular shape (Fig. 14) appear in the core through which posts 52 of the support plates 37 extend. As seen in Fig 21 central core second cap component 76 is formed with a triangular recess 94, 105 (Fig 21) which has a through hole 107 for the fixing screw 68 and which receives triangular post 44 on the inner face of support plate 30, that post also being formed with a through hole 40 for fixing screw 68. In assembly the threaded end of post 60 is held by the fixing screw 68 against the inner face of recess 94 and the support plate 39 is held non-rotatably to the second cap 76. Sockets 92 in the top cap receive connector formations 56 of support plates 37 and thc core components 75, 76 dcfinc a further series of triangular openings through which posts of the support plates 37 extend. Sockets corresponding to the sockets 92 are also formed in the first cap 72, are not visible in Fig. 10 but are apparent in Fig. 22. In the assembled cube, the inner component 70 is a small spacing away from the core and spring 66 biases the fixed cube towards the core and towards the movable cubes so that the cubes are held in contact with one another at a desired level of pressure between them to make the puzzle easy to manipulate with frictional forces at a desirable level for manual rotation of the groups of pieces and to avoid over-tightness or over-looseness, the use of spring 66 permitting manufacturing tolerances to be accommodated and reproducible handling properties to be imparted to the cube. A float of +1mm in a cube of about 45 mm may be appropriate, i.e. the possible travel in this embodiment is about 2 mm, the normal position of the fixed cube being about the mid-point of its travel.

Fig. II is a perspective view further illustrating the relationship between fixed cube inner component 70, core cap 72, post 60 and guide plate 39. In Fig 12 the cover for the fixed cube appears, a guide plate 77 of the second group is shown and the second core cap 76 is shown between the post 60 and the guide plate 39. Fig 13 is similar except that slider 100 at position 14e appears fitted onto guide plate 39. In Fig. 14 two guide plates 35 of the first group appear and cover 102 appears on the slider 100 to complete thc cube at position 14e. Central core component 74 is added and defines two triangular openings, one being defined by core components 72, 74 for a guide plate of the first group and the other being defined by core members 74, 76 for a guide plate of the second group. In Fig. 15 the cube at position 1 4a appears on one of the guide plates 35 and a slider appears on the other visible guide plate 35.

Figs 16 -21 show steps in a possible assembly procedure for the cube. In Fig. 16 post 60 and spring 66 are fitted within fixed inner component 70 of the cube 12, first core cap 72 is in position on the post 60, the guide plates 35 of the first set are fitted in place and the central piece 74 of the core has been added, trapping the guide plates 35 between the core components 72, 74 so that they are held firmly in position. As shown the cover for cube 12 is not in place so that the post 60 can be introduced through the hub in inner component 70. Cubes 14a, Mc, 14g with sliders and caps pre-assemblcd are fitted onto the support plates 54 with one of the hooks defined by post 25 and pad 28 cngaged into the arcuatc recess 41 in the vertex facing away from the fixed cube, giving the partly assembled state of Fig. 17. The second set of three support plates 37 and the core top cap 76 are then added as at Fig. 18, after which cubes I 4b, I 4d and I 4f with sliders and caps pre-assembled are fitted onto the support plates 37, only the cubes at positions 14d, I 4f appearing in Fig. 19 and cube I 4b remaining to be fitted. Fig 20 is a view of the partly assembled puzzle in the same assembly state as Fig. 19 but from a viewing direction showing the end of the post 60 opposite to the fixed cube and with the post lying in the viewing direction with the cubes 14b and 14d in place, showing the core cap 76 having in its outer surface triangular recess 105 for receiving correspondingly shaped post 44 on the inner face of support plate 39. Post 60 having threaded bore 107 is located beneath recess 105. Fig 21 is similar to Fig 20 except that pre-assemblcd cube 14b has been added. Slider 100 is fitted onto support plate 39, after which the two components are offered to core cap 76. Fixing screw 68 is then inserted through the tubular hub in slider 100 and through support plate 39 and second core cap 76 into bore 107 of the post and tightened to hold the parts of the puzzle together. Caps 102 are then glued or welded to the fixed cube 12 and to complete the cube 14e. As previously mentioned, thelt will be noted that the present embodiment does not suffer from "final piece" issues, there being no difficuhy in simply lowering slider 100 and sup[port plate 29 into position and completing puzzle assembly.

It will be appreciated that modifications may be made to the embodiment described above without departing from the invention. For example, although the resilient means in the present embodiment is a coil spring, other forms of resilient member e.g. a leaf spring or a body of elastomeric material could be used. The disclosed embodiment employs cubical pieces whose outer components have planar faces which may be coloured or marked as is conventional in puzzles of this kind. The faces may however be non-planar and may be configured to represent an object e.g. a human, animal or toy figure as in US 6210723 (Kremer). Although the fixed piece is in present embodiments received in a socket in the core and differs somewhat from the other pieces, it could be attached to a fixed plate like the guide plates 37, 39 but having three edges coinciding with the division planes so that rotation in any of them is prevented. In that case three corners of the fixed plate may have arcuate recesses permitting a piece of the same construction as the movable pieces to be fixed thereto, but of course there would be no provision for a spring for setting a dcsircd tightness in the puzzle

Claims (7)

1. <claim-text>CLAIMS1. A manipulative puzzle in the form of a 2 x 2 x 2 cube having a core supporting one piece in fixed position relative to the core and seven pieces that are rotatable in groups of four relative to the core, wherein the fixed piece is supported for sliding movement towards and away from thc core and is positioned at a spacing from the core, resilient means biasing the fixed piece towards the movable pieces.</claim-text> <claim-text>2. The puzzle of claim 1, wherein the core is formed with a socket in which said one piece is non-rotatably received, a post extending from said one piece into the core and said resilient means bcing in compression between said one piece and the post for biasing said one piece towards the core.</claim-text> <claim-text>3. The puzzle of claim 2, wherein said one piece comprises inner and outer portions for fastening together during assembly of the puzzle, the inner portion having a tubular hub providing a route for insertion of the post through it and into the core.</claim-text> <claim-text>4. The puzzle of claim 2 or 3, wherein said resilient means is a coil spring on the post.</claim-text> <claim-text>5. The puzzle of claim 2, 3 or 4, wherein the post extends through the core and is secured to it by a fixing member at an end remote from the fixed piece.</claim-text> <claim-text>6. The puzzle of claim S wherein the fixing member is a screw.</claim-text> <claim-text>7. The puzzle ofclaim 5 or 6, wherein at least one rotatable piece comprises inner and outer portions for fastening together during assembly of the puzzle, the inner portion having a tubular hub providing a route for insertion of the fixing member through it and into the post.</claim-text> <claim-text>8. The puzzle of any of claims 2-7, wherein the core is formed as a plurality of components and the post passes to or through each of them.</claim-text> <claim-text>9. The puzzle of claim 8, wherein guide plates for the movable pieces are supported by and held in fixed position between components of the core.</claim-text> <claim-text>10. The puzzle of claim S or 9, wherein the core comprises three components.</claim-text> <claim-text>II. The puzzle of any preceding claim, wherein the core is at least partly hollow.</claim-text> <claim-text>12. A manipulative puzzle comprising eight interconnected pieces in a 2 x 2 x 2 cube and having three orthogonal planes in which groups of four pieces can be rotated to exchange relative positions, said puzzle comprising a body, one piece supported in fixed rotational position relative to the body and seven pieces supported for rotational movement relative to the body, wherein said one piece is supported at a spacing from the body for sliding movement towards and away from the body and resilient means biases said one piece towards the body and towards contact with the slideable pieces.</claim-text> <claim-text>13. A manipulative puzzle comprising eight interconnected pieces in a 2 x 2 x 2 cubical arrangement and having three orthogonal planes in which groups of four pieces can be rotated to exchange relative positions, said puzzle comprising: a body; a piece supported by the body in fixed position relative thereto; seven support plates carried by the body and having the outline of spherical triangles occupying an oetant of a circle with gaps between the plates adjacent the division planes for piece rotation; and seven pieces moveable relative to said body, slideably supported on the support plates and connected thereto by hook formations at their vertices that fit into said gaps and locate behind said plates.</claim-text> <claim-text>14. The puzzle of claim 13, wherein the body comprises at least two components and a plurality of the support plates have connector formations that fit between the components for supporting the plates in fixed position relative to the body.</claim-text> <claim-text>15. The puzzle of claim 13 or 14, wherein the body comprises first, second and third components, a first group of three support plates have connector formations that fit between the first and second body components and a second group of three components have connector formations that fit between the second and third body components.</claim-text> <claim-text>16. The puzzle of claim 15, wherein the support plates of the first group have arcuate formations at vertices furthest from the fixed piece for receiving adjacent hook formations of a group of pieces to be rotated.</claim-text> <claim-text>17. The puzzle of claim 15 or 16, wherein the support plates of said plurality have connector formations on interior faces thereof dcfincd by posts of non-circWar profile that fit through corresponding apertures defined by adjacent components of the core and by feet that fit into sockets in the components.</claim-text> <claim-text>18. The puzzle of claim 17, wherein the feet have first and second ends that fit into respective sockets in the adjacent components.</claim-text> <claim-text>19. The puzzle of claim 17 or 18, wherein the posts are of generally triangular profile.</claim-text> <claim-text>20. The puzzle of any of claims 15 -19, wherein the first body component is formed with a three-sided socket into which the fixed piece fits.</claim-text> <claim-text>21. The puzzle of any of claims 15-20, wherein the seventh support plate has on its interior face a connector formation in the form of a non-circular post that locates into a corresponding socket in the third body component.</claim-text> <claim-text>22. The puzzle of claim 21, wherein the post and socket arc of generally triangular profile.</claim-text> <claim-text>23. The puzzle of any of claims 17-22, wherein the core components are secured togcther by a post having a first end located within the fixed piece, passing through the body and having a second end within a piece position in a layer of pieces not including the fixed piece and diagonally opposite to the fixed piece.</claim-text> <claim-text>24. The puzzle of claim 23, wherein the pieces are formed with inner and outer components, the inner components being formed with tubular hubs giving access to the first and second ends of the posts.</claim-text> <claim-text>25. The puzzle of claim 24, wherein the core components are secured together by a fixing scrcw passed through the hub of the inner piccc component at the position diagonally opposed to the fixed piccc and into the second end of the post.</claim-text> <claim-text>26. The puzzle of claim 24 or 25, wherein the pieces comprise three-sided inner components and three-sided outer components welded to them.</claim-text> <claim-text>27. The puzzle of claim 26, wherein the faces of the outer components are individually coloured or marked.</claim-text> <claim-text>28. The puzzle of claim 26, wherein the faces of the outer components are shaped together to form a design.</claim-text> <claim-text>29. A manipulative puzzle substantially as hereinbcfore described with reference to and as illustrated in the accompanying drawings.</claim-text> <claim-text>30. A manipulative puzzle comprising interconnected pieces in a cubical arrangement and having three orthogonal planes in which groups of pieces can be rotated to exchange relative positions, said puzzle comprising: a body; support plates carried by the body and having the outline of spherical triangles occupying an octant of a circle with gaps between the plates adjacent the division planes for piece rotation; and pieces moveable relative to said body, slideably supported on the support plates and connected thereto by formations that slide within and locate behind the gaps; wherein the body comprises a plurality of components between which formations on the support plates are trapped, and a post extends through the body with a fixing screw at at least one of its ends for securing the body components together.</claim-text> <claim-text>31. A 2 x 2 x 2 puzzle according to claim 30.</claim-text> <claim-text>32. A 4 x 4 x 4 puzzle according to claim 30.Amendments to the claims have been filed as follows:-CLAIMS1. A manipulative puzzle in the form of a 2 x 2 x 2 cube having a core supporting one piece in a fixed rotational position relative to the core and seven pieces that are S rotatable in groups of four relative to the core, wherein the fixed piece is supported for sliding movement towards and away from the core and is positioned at a spacing from the core, resilient means biasing the fixed piece towards the movable pieces.
2. 2. The puzzle of claim 1, wherein the core is formed with a socket in which said one piece is non-rotatably received, a post extending from said one piece into the core and said resilient means being in compression between said one piece and the post for biasing said one piece towards the core.
3. 3. The puzzle of claim 2, wherein said one piece comprises inner and outer portions for fastening together during assembly of the puzzle, the inner portion having a tubular hub providing a route for insertion of the post through it and into the core.
4. 4. The puzzle of claim 2 or 3, wherein said resilient means is a coil spring on the post.
5. 5. The puzzle of claim 2, 3 or 4, wherein the post extends through the core and is secured to it by a fixing member at an end remote from the fixed piece.
6. 6. The puzzle of claim 5 wherein the fixing member is a screw. * * . * .s* r
7. 7. The puzzle of claim 5 or 6, wherein at least one rotatable piece comprises inner * * and outer portions for fastening together during assembly of the puzzle, the inner portion having a tubular hub providing a route for insertion of the fixing member through it and into the post. * *8. The puzzle of any of claims 2-7, wherein the core is at least partly hollow. a9. The puzzle of any of claims 2-8, wherein the core is formed as a plurality of components and the post passes to or through each of them.10. The puzzle of claim 9, wherein the core comprises three components.11. The puzzle of claim 10, wherein guide plates for the movable pieces are supported by and held in fixed position between components of the core.12. The puzzle of claim 11, wherein seven support plates are carried by the core and have the outline of spherical triangles occupying an octant of a circle with gaps between the plates adjacent the division planes for piece rotation, and the seven pieces inoveable relative to said core are slideably supported on the support plates and connected thereto by hook formations at their vertices that fit into said gaps and locate behind said plates.13. The puzzle of claim 12, wherein the support plates have connector formations that fit between the core components for supporting the plates in fixed position relative to the core.14. The puzzle of claim 13, wherein a first group of three support plates has connector formations that fit between first and second core components and a second group of three components has connector formations that fit between second and third core components. . 25 15. The puzzle of claim 14, wherein the support plates of the first group have arcuate formations at vertices furthest from the fixed piece for receiving adjacent hook *: formations of a group of pieces to be rotated.16. The puzzle of claim 14 or 15, wherein the support plates of said plurality have connector formations on interior faces thereof defined by posts of non-circular profile that fit through corresponding apertures defined by adjacent components of the core and by feet that fit into sockets in the components. p.17. The puzzle of claim 16, wherein the feet have first and second ends that fit into respective sockets in the adjacent components.18. The puzzle of claim 16 or 17, wherein the posts are of generally triangular profile.19. The puzzle of any of claims 14-18, wherein the seventh support plate has on its interior face a connector formation in the form of a non-circular post that locates into a corresponding socket in the third body component.20. The puzzle of claim 19, wherein the post and socket are of generally triangular profile.1.5 21. The puzzle of any preceding claim, wherein outer faces of the pieces are individually coloured or marked.22. The puzzle of any of claims 1 -20, wherein the faces of the outer components are shaped together to form a design.23. A manipulative puzzle substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. * * . * ** * * * * * 4 * **S*..... 30 * *</claim-text>