WO2018060909A9

WO2018060909A9 - Building blocks and building block assemblies

Info

Publication number: WO2018060909A9
Application number: PCT/IB2017/055948
Authority: WO
Inventors: Tang CHAN; Yeung WONG
Original assignee: Chan Tang; Wong Yeung
Priority date: 2016-09-28
Filing date: 2017-09-28
Publication date: 2019-03-07
Also published as: CN110520204B; CN110520204A; WO2018060909A1

Abstract

A building block (100) comprising a main body, a panel portion (124) on the main body, a first surface (123) on one side (120) of the panel portion (124), a second surface (143) on a second side (140) of the panel portion (124), the first surface (123) and the second surface (143) being opposite facing surfaces, and one connector pair or a plurality of connector pairs (122, 142). The connector pair (122, 142) comprises a male connector (122) having a first coupling axis (X-X') defining a first coupling direction (+X) along the first coupling axis (X-X'), and a corresponding female connector (142) having a second coupling axis (Y-Y') defining a second coupling direction (+Y) along the second coupling axis (Y-Y'). The first coupling axis (X-X') and the second coupling axis (Y-Y') are axes aligned and coaxial, and the second coupling direction (+Y) is opposite to the first coupling axis (X-X'). A bridge bore (137) interconnecting a male connector (122) and a corresponding female connector (142) of a connector pair is formed on the panel portion (124). The male connector (122) comprises a hollow protrusion portion having an interior compartment, and the female connector (142) comprises a receptacle having an inner peripheral wall defining a receptacle compartment (147). The interior compartment, the bridging bore (137) and the receptacle compartment (147) cooperate to form an internal bore extending between the male connector (122) and the female connector (142).

Description

BUILDING BLOCKS AND BUILDING BLOCK ASSEMBLIES

Field

[0001 ] The present disclosure relates to building blocks and building block assemblies.

Background

[0002] Modular and interconnectible building blocks for construction of toys, such as toy figures, toy vehicles, toy houses, toy farms, toy machines, toy models, and other toy assemblies, toy products and toy structures are known and have been recognized for their educational values, for example, in promoting and encouraging creativity, patience and perseverance. Modular and interconnectible toy building blocks are advantageous, for example, many different types of toy assemblies, toy products and toy structures can be built with a small number of well-designed building blocks of basic configurations and the building blocks can be re-used for building of other toy assemblies, toy products and toy structures. Modular and interconnectible building blocks are also used in building industries, for example, as modular components for construction of buildings and structures. Use of modular and interconnectible building blocks has been known to facilitate flexible, expeditious and standardized construction with less manual work requirements and promote productivity. In addition to application as toys and in the building industry, modular and interconnectible toy building blocks are also used for modular construction of tools, equipment, appliances, and many other types of products.

Disclosure

[0003] Modular and inter-connectible building blocks and assemblies comprising modular and interconnectible are disclosed.

[0004] A building block according to the disclosure comprises a main body, a panel portion on the main body, a first surface on one side of the panel portion, a second surface on a second side of the panel portion, the first surface and the second surface being opposite facing surfaces, and one connector pair or a plurality of connector pairs. The he connector pair comprises a male connector having a first coupling axis defining a first coupling direction along the first coupling axis, and a corresponding female connector having a second coupling axis defining a second coupling direction along the second coupling axis. The first coupling axis and the second coupling axis are axes aligned and coaxial, and the second coupling direction is opposite to the first coupling axis. A bridging bore interconnecting a male connector and a corresponding female connector of a connector pair is formed on the panel portion. The male connector comprises a hollow protrusion portion having an interior compartment, and the female connector comprises a receptacle portion having an inner peripheral wall defining a receptacle compartment. The interior compartment, the bridging bore and the receptacle compartment cooperate to form an internal bore extending between the male connector and the female connector.

[0005] In some embodiments, the male connector projects from the first surface and extends in a first projection direction away from the first surface, the first projection direction being defined by a first projection axis which is coaxial with the first coupling axis, and the female connector projects from the second surface and extends in a second projection direction away from the second surface, the second projection direction being defined by a second projection axis which is coaxial with the second coupling axis.

[0006] In some embodiments, the male connector has a first axial extent, the first axial end being measured between a free axial end of the protrusion portion and the first surface in the first coupling direction. The receptacle portion has a second axial extent, the second axial extent being measured between a free axial end of the receptacle portion and the second surface in the second coupling direction. The first axial extent is larger than or equal to the second axial extent.

[0007] In some embodiments, the second axial extent is between 15%-95% of the first axial extent, including, in percentage terms, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90%, 95 of the first axial extent, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0008] In some embodiments, the interior compartment has a third axial extent, and the third extent is between 10% and 100% of the first axial extent, including, in percentage terms, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0009] In some embodiments, the protrusion portion comprises a neck portion, the neck portion being a narrowed portion which is in abutment with or proximal the first surface, and the receptacle portion comprises a neck receptacle portion, the neck receptacle portion defining a narrowed entry aperture to the receptacle portion. The neck receptacle portion is at an axial depth below the second surface, the axial depth being smaller than the first axial extent.

[0010] In some embodiments, the axial depth is a fraction of the first axial extent, and the fraction is between 15%-95% of the first axial extent, including, in percentage terms, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 of the first axial extent, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges. [001 1 ] In some embodiments, the protrusion portion comprises a neck receptacle portion and the neck receptacle portion or a portion thereof is inside the panel portion.

[0012] In some embodiments, the main body comprises a peripheral portion, the peripheral portion including a peripheral wall extending axially between a first connection surface and a second connection surface. The peripheral wall has a fourth axial extent, and the fourth axial extent is between 20% and 100% of the first axial extent, including, in percentage terms, 20, 20, 30, 40, 50, 60, 70, 80, 90, 100, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0013] In some embodiments, the male connector comprises a peripherally extending first peripheral wall which defines the interior compartment of the protrusion portion, and the receptacle portion of the female connector comprises a peripherally extending second peripheral wall, the second peripheral wall including the inner peripheral wall which defines the receptacle compartment and an outer peripheral wall which surrounds the inner peripheral wall. The first peripheral wall and the second peripheral wall are coaxially aligned.

[0014] In some embodiments, the first peripheral wall projects from the first surface of the panel portion and extends in the first coupling direction, and the second peripheral wall depends from the second surface of the panel portion and extends in the second coupling direction.

[0015] In some embodiments, the second peripheral wall forms a tubular portion depending from the second surface and extending in the second coupling direction to approach a second connection surface.

[0016] In some embodiments, the interior compartment, the bridging bore and the receptacle compartment are coaxial and in fluid communication.

[0017] In some embodiments, the protrusion portion comprises a bulged portion, the bulged portion having a maximum radial extent plane at a maximum radial extent level above the first surface. The receptacle portion has a bulged receptacle portion, the bulged receptacle portion having a maximum radial clearance plane at a maximum radial clearance level below the second surface. The maximum radial clearance level is a second fraction of the maximum radial extent level.

[0018] In some embodiments, the second fraction is between 20% and 95%, including, in percentage terms, 20, 20, 30, 40, 50, 60, 70, 80, 90, 95, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges. [0019] In some embodiments, the bulged receptacle portion or a portion thereof is inside the panel portion or the bridging bore.

[0020] A building block herein comprises one or a plurality of connectors to facilitate detachable or releasable mechanical connection between modular building blocks in abutment. The mechanical connection is typically by press-fitting or snap-fitting. The building block comprises one connector or a plurality of connectors on at least one connection surface and building blocks can be stacked with their respective connection surfaces in abutment connect and the connectors on their respective connection surfaces in detachable mechanical engagement.

[0021 ] A building block herein may be a toy building block. A toy building block is typically made of thermoplastics such as ABS (acrylonitrile butadiene styrene), PC (polycarbonate), or other plastic materials that a high degree of strength and rigidity, as well as a small degree of resilience to be slightly resiliently deformable to facilitate press-fit or snap-fit engagement.

[0022] A building block herein may be made of clay, ceramic, porcelain, concrete, or other mouldable materials that have a high rigidity and a very low degree of resilience or virtually no resilience.

[0023] A building block herein may also be made of wood, metals, for example, steel, aluminum, aluminum alloys, or other materials that can be shaped.

[0024] Where a building block is made of a material having a high rigidity with a very low degree of resilience or no resilience, the building block may connect with a building block having a sufficient degree of resilience to facilitate mechanical connection by resilient deformation of the connector(s) thereon.

[0025] In general, a building blocks can be rigid and slightly resilient or non-resilient, and the rigidity and resilience may be selected to suit applications by selecting appropriate materials or appropriate mix of materials.

[0026] A building block herein may be ceramic building block or a porcelain building block. The ceramic or porcelain building block may be in the form of a ceramic brick or a porcelain brick, a ceramic tile or a porcelain tile, a ceramic panel or a porcelain panel, or other forms of ceramic parts or porcelain parts without loss of generality. The ceramic or porcelain building blocks may be interconnected using binding agents such as glue, cement, or mortar to form the modules, assemblies or sub-assemblies, or interconnect wit building blocks made of a rigid and slightly resilient material. [0027] A building block herein typically comprises a main body, a first surface on a first side of the main body, a second surface on a second side of the main body, a peripheral portion extending between the first surface and the second surface, and a plurality of connectors formed on the main body. The main body is typically rigid or semi-rigid and the connectors have peripheral walls which are rigid or semi-rigid and having a small degree of resilience to facilitate snap engagement with corresponding connector through resilient deformation of the engagement portions of the connectors. The connectors are usually formed on a panel portion of the main body. In some embodiments, male connectors are formed on one panel portion and female connectors are formed on another panel portion separate from the panel portion on which the male connectors are formed. In some embodiments, male connectors and female connectors are formed on a common panel portion.

[0028] A connector herein means a building block connector unless the context requires otherwise. A building block connector comprises a connection portion having a coupling axis defining a coupling direction. The connection portion comprises an engagement portion for making closely fitted engagement with a matched connector portion of a matched connector to form a pair of engaged connectors.

[0029] An engagement portion comprises mechanical mating features for making closely fitted engagement with a corresponding engagement portion of a matched connector to form a pair of engaged engagement portions. An engagement portion may be a male engagement portion or a female engagement portion.

[0030] A connector is generally classified as a male connector or a female connector. However, a male connector may comprise a female engagement portion in addition to its inherent male engagement portion and a female connector may comprise a male engagement portion in addition to its inherent female engagement portion.

[0031 ] A male engagement portion comprises male mating features. A male engagement portion typically comprises a protrusion which is shaped and sized for closely-fitted reception of a corresponding female engagement portion. A protrusion adapted for closely-fitted reception of a corresponding female engagement portion is a matched corresponding male engagement portion of that corresponding female engagement portion. A protrusion herein is also referred to as a "protrusion portion", a "protruding member", a "protrusion member", "protrusion body", and "protruding body" and the terms are interchangeably used herein unless the context requires otherwise. [0032] A female engagement portion comprises female mating features. A female engagement portion typically comprises a coupling receptacle which is shaped and sized for closely-fitted reception of a corresponding male engagement portion. A coupling receptacle adapted for closely- fitted reception of a corresponding male engagement portion is a matched corresponding female engagement portion of that corresponding male engagement portion. A receptacle herein means a coupling receptacle of a female building block connector unless the context requires otherwise. A coupling receptacle of a female building block connector is also referred to as a male engagement portion receptacle or a male-connector receptacle.

[0033] A pair of connectors having matched corresponding engagement portions when on separate building blocks are detachably engageable to form a releasable mechanical connection. When the pair of connectors have matched snap engagement portions, the connectors are snap engageable to form a snap engaged connector pair.

[0034] A male engagement portion and a corresponding female engagement portion having matched and compatible mating features will enter into closely fitted engagement when they are brought or moved relatively towards each other with their respective coupling axes aligned and press connected along the aligned coupling axes. The fitted or closely fitted engagement herein may be by interference fit or snap fit. When a pair of matched connectors herein are brought or moved relatively towards each other with their respective coupling axes aligned and then pressed together, the matched connectors will engage and enter into closely fitted engagement.

[0035] A connector has a characteristic radial profile. The radial profile of a connector is characterized by the radial extent of the engagement portion or the engagement portions of the connector between its axial ends. A snap connector is characterized by a non-uniform radial extent in the axial direction, and more particularly by a bulged radial profile.

[0036] A male connection portion comprises a protruding portion which is to enter into a receptacle of a corresponding female connection portion to make releasable mechanical engagement therewith. The protrusion portion may be in the form of a protrusion body, a protruding body, a protrusion member or a protruding member.

[0037] The protrusion portion of a male connection portion projects from a base surface and extends in an axial direction away from the base surface, the axial direction being with respect to the coupling axis of the protrusion portion. A male connection portion comprises a connector head defining its axial end. The axial extent of a protrusion portion, measured along the coupling axis of the male connection portion between the base surface from which it projects and its axial end, defines the height of the protrusion. The protruding body has an outer peripheral wall which defines the mating features of the protrusion portion, including shape, configuration, radial profile and dimensions.

[0038] The protrusion portion of a male snap connector has a radial profile which is defined by its outer peripheral wall. The radial profile of a snap connector is characterized by a non-uniform radial extent in the axial direction. A male snap connector typically comprises a bulged portion having a bulged radial profile and a reduced portion having a reduced radial profile.

[0039] A typical protrusion portion herein is an annular protrusion comprising a first protrusion portion and a second protrusion portion. The first protrusion portion and the second protrusion portion are in series and are aligned on the coupling axis. The first protrusion portion is in abutment with the base surface and the second protrusion portion comprises the axial end, which is usually a free axial end. The first protrusion portion is, in the axial direction, or axially, intermediate the second protrusion portion and the base surface.

[0040] The first protrusion portion is referred to as a neck portion which is supported on the base surface and the second protrusion portion is referred to as a head portion which is supported by the neck portion.

[0041 ] The head portion has an enlarged radial profile compared to the neck portion radial profile, and is also referred to as an enlarged portion. As the profile enlargement is in the radial direction, the head portion is also referred to as a widened portion.

[0042] In general, the head portion is an enlarged portion having a head portion radial profile which is a bulged radial profile, or a bulged profile in short.

[0043] The head portion has an outer periphery which is in the general form of a peripherally extending rib. A peripherally extending rib herein is an annular rib having the radial profile of the head portion radial profile in the peripheral direction. The annular rib is defined by the outer peripheral wall of the protrusion portion and may be continuous or non-continuous. The peripheral direction is orthogonal to the coupling axis and is a tangential direction to a circle defining the annular rib. The annular rib surrounds a core portion of the head portion, and the core portion of the head portion may be solid or hollow. When the core portion is hollow, the head portion is in the form of a hollow shell having an internal compartment. The head portion radial profile and the annular rib has the radial profile of a radial protrusion and defines an engagement portion, and more specifically, defines a male snap engagement portion of a male connection portion. The engagement portion on the head portion of a male connection portion is referred to as a first engagement portion or a first snap engagement portion of the protrusion portion or of the male connection portion for ease of reference. The terms "rib" and "ridge" are equivalent and are used interchangeably herein.

[0044] The bulged head portion has a maximum radial extent defining a maximum radial plane at an axial level with respect to the base surface. The maximum radial plane is a maximum transversal plane, and the axial level of the maximum radial plane is a maximum radial extent level.

[0045] The bulged portion has a lower surface which extends between the maximum radial plane and the base surface. The lower surface is a tapered surface which oppositely faces the base surface. The radial extent of the lower surface of the bulged head portion at an axial level decreases as the axial level moves closer towards the base level of the base surface to define a lower tapered surface. Conversely, the radial extent of the lower surface of the bulged head portion at an axial level increases as the axial level of the lower surface away from the base surface increases. The radial extent of the lower surface of the bulged head portion reaches a local minimum at an axial level where it joins the neck portion.

[0046] The head portion tapers to narrow as it extends axially from the maximum radial extent plane towards the base surface. Conversely, the head portion flares to widen as it extends axially from the base surface towards the maximum radial extent plane.

[0047] The axial free end of the head portion may be flat or rounded. Where the axial free end is flat, the male connector has a flat head. Where the axial end is rounded, the male connector has a rounded head. The rounded head may be in the shape of a dome, a spherical cap, or a rounded boss or other suitable shapes.

[0048] The head portion radial profile extends in a peripheral direction to define an annular outer periphery of the head portion and the neck portion radial profile extends in a peripheral direction to define an annular outer periphery of the neck portion.

[0049] The neck portion has reduced radial profile compared to the head portion radial profile, and is also referred to as a reduced portion. As the profile reduction is in the radial direction, the neck portion is also referred to as a narrowed portion.

[0050] In general, the neck portion is a reduced enlarged portion having a neck portion radial profile which is a tapered radial profile, or a tapered profile in short.

[0051 ] The neck portion has an outer periphery which is in the form of a peripherally extending channel. The peripherally extending channel is an annular channel having the radial profile of the neck portion radial profile in the peripheral direction. The annular channel is defined by the outer peripheral wall of the protrusion portion and may be continuous or non-continuous. The peripheral direction is orthogonal to the coupling axis and is a tangential direction to a circle defining the annular channel. The annular channel, that is, the peripherally extending channel, surrounds a core portion of the neck portion, and the core portion of the neck portion may be solid or hollow. When the core portion is hollow, the neck portion is in the form of a hollow shell having an internal compartment. The neck portion radial profile and the annular channel has the radial profile of a radial indentation and defines an engagement portion, and more specifically, a female snap engagement portion on a male connection portion. The engagement portion on the neck portion of a male connection portion is referred to as a second engagement portion or a second snap engagement portion of the protrusion portion or of the male connection portion for ease of reference. This second engagement portion is a retention portion which is adapted to receive and retain a neck receptacle portion of a female connector. The terms "channel" and "groove" are equivalent and are used interchangeably herein.

[0052] The neck portion has a local maximum radial extent at an axial level where it joins or is in abutment with the head portion. The local maximum radial extent defines a local maximum radial plane, which is also a local maximum transversal plane.

[0053] The neck portion has an outer peripheral surface which extends between the local maximum radial plane and the base surface. The outer peripheral surface is a tapered surface which oppositely faces the base surface. The radial extent of the outer peripheral surface of the neck portion at an axial level decreases as the axial level moves closer towards the base level of the base surface to define a tapered outer peripheral surface. Conversely, the radial extent of the outer peripheral surface of the narrowed neck portion at an axial level increases as the axial level of the outer peripheral surface away from the base surface increases. The radial extent of the outer peripheral surface of the neck portion reaches a local minimum at an axial level where it joins the head portion. The outer peripheral surface is optionally a smooth continuation of the lower surface of the head portion. Where the lower surface of the head portion follows a curved profile to taper, the radial profile of the outer peripheral surface may follow a curved profile which is a curved continuation of the curved profile to taper. In some embodiments, the curved profile follows a radius of curvature equal to half the maximum radial extent.

[0054] Therefore, the neck portion tapers to narrow as it extends axially from the local maximum radial extent plane towards the base surface. Conversely, the neck portion flares to widen as it extends axially from the base surface towards the local maximum radial extent plane. [0055] While the peripheral channel is primarily defined by the outer peripheral surface of the neck portion in cooperation with the base surface, the entire channel may be regarded as being defined by the lower axial end of the enlarged portion, the narrowed neck portion and the base surface in cooperation.

[0056] The channel may have a constant radial extent in the axial direction or may have a tapered radial profile such that the radial extent of the neck portion decreases as its axial level decreases towards the base surface.

[0057] The tapering may follow a curved profile, for example the profile of a convex curve, a straight slope or other desired profiles without loss of generality.

[0058] In general, the axial extent of a protrusion of a connection portion is a fraction of the maximum radial extent of the protrusion, and the fraction is optionally between 20% and 80%, for example, in percentage terms, at 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or any range or ranges defined by a combination of any of the aforesaid values and/or ranges. Typically, the axial extent will be in the higher range of between 50% and 80% where the protrusion has a rounded end or partial spherical end and in the lower range of 15% and 60% where the protrusion has a flat head or flat axial end. For an annular protrusion, the maximum radial extent E is the diameter D of a circle, the circle defines a maximum radial extent plane and the aforesaid fraction is also in respect of the diameter.

[0059] The axial extent between the maximum radial extent level and the axial free end of the protrusion portion is a fraction of the maximum radial extent of the protrusion, and the fraction is optionally between 5% and 50% of the maximum radial extent, E, at the maximum radial extent level, for example, in percentage terms, at 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges. This axial extent of the upper portion of the protrusion will be in the lower range of between 5% and 30% where the protrusion has a flat head or flat axial end, and in the higher range of between 25% and 50% where the protrusion has a rounded end or partial spherical end. When the axial extent of the upper protrusion is 50%, the upper portion has a hemispherical shape.

[0060] The axial extent between the base surface and the maximum radial extent plane of the protrusion is a fraction of the maximum radial extent of the protrusion, and the fraction is optionally between 6% and 30% of the maximum radial extent, E, for example, in percentage terms, at 6, 8, 10, 12, 15, 18, 20, 25, 30, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges. [0061 ] The axial extent of the bulged portion is a fraction of the maximum radial extent of the protrusion, and the fraction is optionally between 5% and 25% of the maximum radial extent, E, for example, in percentage terms, at 5, 10, 15, 20, 25, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0062] The axial extent of the neck portion is a fraction of the maximum radial extent of the protrusion, and the fraction is optionally between 5% and 15% of the maximum radial extent, E, for example, in percentage terms, at 5, 10, 15, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0063] The radial extent of the neck portion is a fraction of the maximum radial extent of the protrusion, and the fraction is optionally between 90% and 99% of the maximum radial extent, for example, in percentage terms, at 90, 91 , 92, 93, 94, 95, 96, 97, 98, 99, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0064] The radial extent of the radial indentation defining the channel of the neck portion is a fraction of the maximum radial extent of the protrusion, and the fraction is optionally between 1 % and 6%, for example, in percentage terms, at 1 , 2, 3, 4, 5, 6 or more, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0065] The protrusion portion or a portion thereof may be a convex annular portion which follows a convex curvature as it extends towards the base surface in the direction of the coupling axis. The convex annular portion may have the shape of a spherical segment having a radius of curvature R, where R is half the value of the maximum radial extent of the maximum radial plane, and an axial extent or height h. The maximum radial plane is usually contained between two smaller radial planes so that the radial extent of the convexly curved portion increases from a first radial extent defined by a first smaller radial plane to the maximum radial extent and then decreases to a second radial extent defined by a second smaller radial plane as the curved portion extends along the direction of the coupling axis, the radial plane extending in a transversal direction or a lateral direction which is orthogonal to the coupling axis.

[0066] The protrusion portion between the base surface and the maximum radial plane may be in the shape of a spherical segment or a truncated cone, i.e., frusto-cone. The axial height between the base surface and the maximum radial plane is optionally between 20% and 85% of R, where R is the radius of the sphere defining the spherical segment, for example, in percentage terms, at 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges. [0067] Where the neck portion of the protrusion portion in abutment with the base surface is in the shape of a spherical segment, the neck portion has a shape of a lower spherical segment and has a convexly curved profile in the radial direction. When the neck portion is so shaped, the neck portion has a smaller radial extent at the base surface and a local maximum radial extent at an axial separation from the base surface.

[0068] The radial extent of the neck portion at the base surface is at a fraction of the maximum radial extent, and the fraction is optionally between 90% and 98.8%, for example, in percentage terms, at 90, 92, 94, 96, 98, 98.8, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0069] The local maximum radial plane is elevated above the base surface and a radial plane having a smaller radial extent is in abutment with the base surface.

[0070] The neck portion may taper to join the base surface and joins at a joining angle. The tapering may follow a convexly curved profile, may have a constant slope, or other desired tapering manner. The joining angle is an acute angle which is optionally between 50 degrees and 88 degrees, for example, in degree terms, 50, 55, 60, 65, 70, 75, 70, 80, 85, 88, or a range or any ranges defined by a combination of any of the aforesaid values and/or ranges.

[0071 ] The protrusion portion, for example, the bulged portion or the reduced portion, may comprise a cylindrical body or a prismatic body which projects away from the base surface, with a tapered portion formed at a peripheral region in abutment with or in proximity to the base surface.

[0072] A snap connector or the engagement portion of a snap connector herein is axis- symmetrical. An axis symmetrical engagement portion has axis-symmetrical mating feature profiles. An axis-symmetrical engagement portion or connector typically has a circular cross section at an axial defined by the coupling axis of the engagement portion or the connector. In some embodiments, the engagement portion may not be exactly axis-symmetrical but has a square cross-section or a cross-section of a regular polygon having five side, six sides, seven sides, eight side, nine sides, ten side or more. A snap connector herein includes both the axis- symmetrical and non-axis-symmetrical types unless the context requires otherwise.

[0073] On the other hand, the radial extent of a protrusion portion of a press-fit or interference-fit connector without snap-fit features is substantially uniform in the axial direction.

[0074] A female connection portion comprises a coupling receptacle for reception of a protrusion portion of a corresponding male connector. More specifically, a female connection portion comprises a coupling receptacle, or receptacle in short, for closely-fitted reception of a protrusion portion of a corresponding male connection portion to facilitate snap engagement. When a male engagement portion is in closely fitted engagement with a female engagement portion, the male engagement portion is received by the receptacle and at least a portion of the male engagement portion projects into and is received inside the receptacle compartment.

[0075] The receptacle of a female connector comprises a receptacle compartment and a receptacle entry through which an axial end of a protrusion of a corresponding male connection portion is to enter the receptacle compartment. The receptacle comprises an inner peripheral wall which defines the receptacle compartment, the receptacle entry, as well as a receptacle entry plane and an entry aperture at the receptacle entry. The entry aperture is typically on an axial end of the receptacle and is also referred to as an access aperture and the receptacle entry plane is orthogonal to the coupling axis. The entry aperture defines a minimum radial clearance of the receptacle which in turn defines a maximum radial extent of the protrusion or the bulged portion of a protrusion that can enter into the receptacle without radial deformation of the receptacle entry or the male connector protrusion. The coupling receptacle extends in the axial direction away from the receptacle entry to define an axial extent of the receptacle compartment. The axial extent of a receptacle, as measured along the coupling axis of the receptacle between the axial ends of the inner peripheral wall which defines the receptacle compartment, defines the height of the receptacle. The inner peripheral wall of the receptacle defines the shape, configuration, dimensions of the receptacle compartment. The receptacle may be in the form of a receptacle portion, a receptacle body, or a receptacle member. In some embodiments, a female connector comprises a peripheral wall which defines the receptacle. The peripheral wall may comprise an inner peripheral wall which defines the receptacle compartment and the receptacle compartment radial profile and an outer peripheral wall which surrounds the inner peripheral wall and defines the outer periphery of the receptacle. The peripheral wall may be a continuous wall or a non- continuous wall. In some embodiments, the outer peripheral wall of the receptacle depends from the panel portion and has a substantial portion of its axial extent which is spaced apart from or independent of the panel portion. For example, the outer peripheral wall may have, in percentage terms of its axial extent or of the maximum radial extent of the receptacle compartment, 55, 60, 65, 70, 75, 80, 90, 95, 100, or a range or any ranges defined by a combination of any of the aforesaid values and/or ranges which is laterally separated from the panel portion so that there is radial spatial separation between the outer peripheral wall and the panel portion from which the receptacle depends. In some embodiments, a minor portion of the axial extent of the receptacle is spaced apart from or independent of the panel portion, and the minor portion, in percentage terms of its axial extent or of the maximum radial extent of the receptacle compartment, is 5, 6, 7, 8, 9, 9, 10, or a range or any ranges defined by a combination of any of the aforesaid values and/or ranges.

[0076] A female snap connector comprises a snap-fit receptacle which is shaped and dimensioned for closely fitted engagement of a male snap engagement portion. When a female snap connector and a male snap connector are in closely-fitted snap engagement, the male engagement portion is subject to a small radially inward compression force exerted radially inwardly by the receptacle functioning as a female engagement portion, and the receptacle is subject to a small radial outward expansion force which is exerted radially outwardly by the male engagement portion.

[0077] The receptacle compartment of a female connector has a radial profile which is defined by the inner peripheral wall of the receptacle. The radial profile of the receptacle compartment of a female snap connector is characterized by a non-uniform radial extent in the axial direction, and typically includes a bulged radial profile of a bulged receptacle portion and a reduced radial profile of a reduced receptacle portion in the axial direction. The terms receptacle, coupling receptacle, snap-fit receptacle, receptacle portion, receptacle body, and receptacle member are interchangeably used herein unless the context requires otherwise.

[0078] The entry aperture is on or at one axial end of the receptacle and is an annular aperture which provides access for a male engagement portion so that a male engagement portion can enter into the receptacle compartment through that axial end and through the entry aperture and then enter into closely-fitted engagement with the receptacle. A receptacle may have an entry aperture on each of the two axial ends of the receptacle to facilitate entry or exit of a protrusion portion of a male connector from a selected one of the two axial ends.

[0079] The entry aperture has or may have a radial clearance which is smaller or slightly smaller than the maximum radial extent of a male engagement portion, and the maximum radial extent of a male engagement portion is typically located on the bulged portion of the male connector protrusion. A smaller radial clearance at the entry aperture than the maximum radial extent of the bulged portion usually means a radial constriction at the axial end of the receptacle. The bulged portion of a male connection means would need to overcome the radial constriction in order to enter the receptacle compartment from outside the receptacle compartment or to leave the receptacle if already inside the receptacle compartment. A minimum radial clearance extent of the receptacle is defined at the entry aperture.

[0080] A receptacle may comprise a first receptacle portion having a first receptacle compartment and a second receptacle portion having a second receptacle compartment. The first receptacle portion and the second receptacle portion are in series and are aligned on the coupling axis. The first receptacle portion has an axial end comprising the receptacle entry and the second receptacle portion extends axially away from the first receptacle portion and the receptacle entry. The first receptacle portion is to surround and snap on the neck portion of a corresponding male engagement portion upon snap engagement therewith and is referred to as a neck receptacle portion. The neck receptacle portion is also referred to as a neck portion engagement portion and comprises a neck receptacle compartment. The second receptacle portion is to surround and snap on the head portion of a corresponding male engagement portion upon snap engagement therewith and is referred to as a head receptacle portion. The head receptacle portion is also referred to as a head portion engagement portion and comprises a head receptacle compartment. The two receptacle portions, namely, the head receptacle portion and the neck receptacle portion, may be separate or integrally formed.

[0081 ] The engagement portion of a receptacle portion is an annular receptacle portion defined by a portion of the inner peripheral wall of the receptacle defining the receptacle portion. The engagement portion may be in the embodiments of an annular bracket portion, an annular bracket member, an annular collar portion, or an annular collar member. In some embodiments, a receptacle portion has an access aperture at each of its axial ends to facilitate entry and/or exit of a matched male engagement portion at either axial end.

[0082] In some embodiments, the receptacle may have only one receptacle portion, for example, only the head receptacle portion or only the neck receptacle portion.

[0083] The head receptacle portion comprises a head receptacle compartment which is adapted for making snap engagement with the head portion of a corresponding male connector, and has a radial clamping profile which is complementarily shaped and sized to match the radial profile of the bulged portion of the corresponding male connector.

[0084] The head receptacle portion is an enlarged receptacle portion, also referred to as a widened receptacle portion, or an enlarged portion in short. The head receptacle portion has a head receptacle portion radial profile which is an enlarged radial profile compared to the neck receptacle portion radial profile. The head receptacle portion radial profile extends in a peripheral direction to define an annular inner periphery of the head receptacle portion. The head receptacle portion radial profile and the inner periphery of the head receptacle portion is defined by a portion of the inner peripheral wall of the receptacle defining the head receptacle portion. The engagement portion of a head receptacle portion is typically in the form of an annular clamp or clip, and in example embodiments in the form of an annular bracket portion, an annular bracket member, an annular collar portion, or an annular collar member. The maximum radial clearance extent of the receptacle is usually defined in the head receptacle portion.

[0085] The portion of the inner peripheral wall of the receptacle defining the head receptacle portion and the head receptacle compartment has a radial profile of an indentation or a recess, with the indentation or access inwardly facing the coupling axis. The indentation has a radial profile which defines the head receptacle portion radial profile. The radial profile may be angled or curved and extends peripherally in a peripheral direction, that is annularly, to define the head receptacle compartment and its boundary. The peripheral direction is orthogonal to the coupling axis and is a tangential direction to a circle defining the annular clamp or clip. The annular clamp or clip is in the form of an annular channel which surrounds a core portion of the head receptacle portion. The head receptacle portion defines a female snap engagement portion of the female connection portion, and is referred to as a first engagement portion or a first snap engagement portion of the receptacle, or of the female connection portion, for ease of reference. The terms "channel" and "groove" are used interchangeably herein.

[0086] The head receptacle compartment has a maximum radial extent defining a maximum radial clearance and a maximum radial plane at an axial level referred to a maximum radial extent level. The maximum radial plane is also a maximum transversal plane. The radial extent of the head receptacle portion decreases as the axial distance from the maximum radial extent level increases. Specifically, the radial extent of the head receptacle portion decreases as the head receptacle portion extends away from the maximum radial extent level and towards the receptacle entry, and the radial extent of the head receptacle portion decreases as the head receptacle portion extends away from the maximum radial extent level and away from the receptacle entry. Therefore, the head receptacle portion tapers to narrow as its axial distance away from the maximum radial extent plane or the maximum radial extent level increases. Conversely, the head receptacle portion flares to widen as it extends axially towards the maximum radial extent plane or the maximum radial extent level.

[0087] The axial end of the head receptacle portion distal to the receptacle entry may be flat or curved, for example, may have the shape of a spherical cap or other desired shapes.

[0088] The neck receptacle portion comprises a neck receptacle compartment which is adapted for making snap engagement with the neck portion of a corresponding male connector and has a radial clamping profile which is complementarily shaped to match the radial profile of the neck portion of the corresponding male connector. [0089] The neck receptacle portion is a reduced receptacle portion compared to the head receptacle portion radial profile. The neck receptacle portion is a reduced receptacle portion, since it has a neck receptacle portion radial profile which is smaller than the radial profile of the head receptacle portion radial profile. The reduced receptacle portion is also referred to as a narrowed receptacle portion, or a reduced portion in short. The neck receptacle portion radial profile is defined by a portion of the inner peripheral wall of the receptacle which defines the neck receptacle portion and the inner periphery of the neck receptacle portion. The neck receptacle portion radial profile extends in a peripheral direction to define an annular inner periphery of the neck receptacle portion. The portion of the inner peripheral wall of the receptacle which defines the neck receptacle portion and the neck receptacle compartment has a radial profile of an indentation or a recess, and the indentation or access is inwardly facing the coupling axis and the centre of the maximum radial plane of the head receptacle portion. The indentation has a radial profile which is or which defines the neck receptacle portion radial profile. The radial profile may be angled or curved and extends peripherally in a peripheral direction, that is annularly, to define a neck receptacle compartment and its boundary.

[0090] The engagement portion of an example neck receptacle portion is in the form of an annular clamp or an annular clip which surrounds and defines the neck receptacle portion. The annular clamp or clip may have a radial profile of a clamping bracket or a clamping collar. The neck receptacle portion in exemplary embodiments is in the form of an annular bracket portion, an annular bracket member, an annular collar portion, or an annular collar member. The terms "bracket" and "collar" are interchangeably used herein and shall bear the same meaning unless the context requires otherwise. A clamping bracket herein is an inclined bracket having a recess or indentation facing the coupling axis and the centre of the maximum radial plane of the head receptacle portion. The bracket extends peripherally in a peripheral direction to define a neck receptacle compartment portion and its boundary. The peripheral direction is orthogonal to the coupling axis and is a tangential direction to a circle defining the annular clamp or clip. The neck receptacle portion defines a female snap engagement portion of the female connection portion, and is referred to as a second engagement portion or a second snap engagement portion of the receptacle, or of the female connection portion, for ease of reference. This second engagement means, similar to the first engagement means, is a retention portion defining a female retention means. The minimum radial clearance extent of the receptacle is usually defined in the neck receptacle portion. [0091 ] The reduced receptacle portion has a local maximum radial extent defining a local maximum radial plane at an axial level referred to a local maximum radial extent level. The local maximum radial plane is also a local maximum transversal plane. The radial extent of the neck receptacle compartment decreases as the axial distance away from the local maximum radial extent level towards the receptacle entry increases. Specifically, the radial extent of the neck receptacle compartment decreases as the neck receptacle compartment extends away from the local maximum radial extent level and towards and joins the receptacle entry. The neck receptacle compartment is a tapered receptacle portion which tapers to narrow as it extends axially towards the receptacle entry. Conversely, the neck receptacle compartment flares to widen as it projects axially away from the receptacle entry.

[0092] The tapered entry end of the neck receptacle portion is optionally shaped and sized to operate as an engagement portion, or more specifically a male engagement portion, for engaging with or snap on the narrowed neck portion of the corresponding male connection portion, for example, by wedged engagement. Therefore, this tapered entry end be regarded as a third snap engagement portion of the receptacle.

[0093] The tapering may follow a curve, for example, a concave curve, a straight slope or other desired profiles without loss of generality.

[0094] The receptacle of a female connection portion is adapted to accommodate the protrusion of a male connection portion such that when two building blocks having matched connection means are stacked and their matched corresponding connection means in releasable engagement, the corresponding connection surfaces of the building blocks are in flush abutment and even contact. To meet the accommodation requirements, the axial end or ceiling of the receptacle compartment which is distal to the entry end would need to be at an axial level sufficient to accommodate the protrusion.

[0095] Where the entry end of the receptacle is at the axial level of the connection surface, as is usually the case, the ceiling end of the receptacle would be at an axial level corresponding to the axial extent of the protrusion from the connection surface, unless the ceiling end is an open end that allows the protrusion to pass through. In general, the axial extent of the receptacle compartment is a fraction of the maximum radial extent, E, of the protrusion or of the receptacle, and the fraction is optionally between 15% and 80%, for example, in percentage terms, at 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or a range or any ranges defined by a combination of any of the aforesaid values and/or ranges. Typically, the axial extent will be in the higher range of between 50% and 80% where the protrusion has a rounded end or partial spherical end and in the lower range of 15% and 60% where the protrusion has a flat head or flat axial end.

[0096] A head receptacle portion which is adapted to snap on the bulged portion has a radial clamping profile which is complementarily shaped to match the radial profile of the bulged of the head portion.

[0097] In order to provide sufficiently effective snap griping on the bulged portion, the axial extent of the radial clamping profile of the head receptacle portion, which is determined by the radial profile of the annular bracket, would be comparable to the axial extent of the bulged portion of the corresponding male engagement portion. In general, the axial extent of the head receptacle portion would be a fraction of the maximum radial extent of the bulged portion, and the fraction would optionally be between 10% and 40%, for example, in percentage terms, at 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0098] The head receptacle portion is optionally symmetrical about a radial plane of symmetry, which corresponds to the maximum radial extent plane of the bulged receptacle portion or the bulged portion of the protrusion on snap engagement. The plane of symmetry divides the head receptacle portion into symmetrical halves about the radial plane of symmetry. The head receptacle portion tapers to narrow as it extends axially away from the maximum radial extent plane to taper. The head receptacle portion optionally follows a concave profile or has a concave radial profile as it extends axially to taper. Optionally, the concave profile follows or matches the convex profile of the corresponding bulged portion. In some embodiments, the concave profile follows a concave curvature having a diameter equal to or comparable to the maximum radial extent of the bulged portion. The tapering may follow a straight slope or other desired profiles without loss of generality. The concave curve may have a radius of curvature comparable to half the maximum radial extent E.

[0099] The radial extent of the head receptacle portion at an axial end of the head receptacle portion where symmetry about the plane of symmetry ends is a fraction of the maximum radial extent of the bulged receptacle portion, and the fraction would optionally be between 95% and 99%, for example, in percentage terms, at 95, 96, 97, 98, 99, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0100] The neck receptacle portion has an axial extent to provide snap grip on the neck portion of the male connector. The axial extent is a fraction of the maximum radial extent of the bulged portion which, in percentage terms, is optionally between 2 and 10, for example, at 2, 3, 4, 5, 6, 7, 8, 9, 10, or a range or any ranges defined by a combination of any of the aforesaid values and/or ranges.

[0101 ] In order to provide sufficient or effective snap clamping on the neck portion of the protrusion, the axial extent of the radial clamping profile of the neck receptacle portion, which is the radial profile of the annular bracket, would be comparable to the axial extent of the neck portion of the corresponding male engagement portion. In general, the axial extent of the neck receptacle portion would be a fraction of the radial extent of the neck portion at the base surface, and the fraction would optionally be between 10% and 35%, for example, in percentage terms, at 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 35, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0102] The axial extent of the neck receptacle portion can be expressed as a fraction of the maximum radial extent of the receptacle, and the fraction would optionally be between 1 .9% and 5%, for example, in percentage terms, at 1 .9, 2, 2.0, 2.5, 3, 3.5, 4, 4.0, 4.5, 5, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0103] The neck receptacle portion tapers to narrow as it extends axially towards the access aperture to define a narrowed access aperture to facilitate snap fit.

[0104] As a result of the tapering, the access aperture at the tapered axial end of the neck receptacle portion has a radial extent which is a fraction of the maximum radial extent of clearance of the internal compartment of the receptacle, and the fraction is optionally between 85% and 96%, for example, in percentage terms, at 85, 90, 95, 96, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

[0105] As a result of the tapering, the inner peripheral wall of the neck receptacle portion is at an inclination angle to a radial plane at the access aperture axial end of the neck receptacle portion. The inclination angle is optionally between 50 degrees and 88 degrees, for example, in degree terms, 50, 55, 60, 65, 70, 75, 70, 80, 85, 88, or any range or ranges defined by a combination of any of the aforesaid values and/or ranges. Preferably, the inclination angle corresponds to the joining angle to facilitate closely fitted engagement between the neck receptacle portion and the neck portion.

[0106] Where the receptacle comprises both the neck receptacle portion and the head receptacle portion, both the neck receptacle portion and the head receptacle portion may be defined by an integrally formed peripheral wall of the receptacle, and the axial extent of the peripheral wall of the receptacle would optionally be between 30% and 85% of R, for example, in percentage terms, at 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or a range or any ranges defined by a combination of any of the aforesaid values and/or ranges.

Figures

[0107] The disclosure is described by way of example with reference to the accompanying figures, in which:

Figure 1 is a perspective view of an example building block 100 from one side,

Figure 1 A is a perspective view of the building block of Figure 1 from another side,

Figure 1 B is a plan view of the building block of Figure 1 from one side,

Figure 1 C is a cross-sectional view of the building block of Figure 1 along a section line A-A', Figure 1 D is an enlarged view of a portion of the Figure 1 C,

Figure 2 is a perspective view of an example building block 200 from one side,

Figure 2A is a perspective view of the building block of Figure 2 from another side,

Figure 2B is a plan view of the building block of Figure 2 from one side,

Figure 2C is a cross-sectional view of the building block of Figure 2 along a section line B-B', Figure 2D is an enlarged view of a portion of the Figure 2C,

Figure 3 is a perspective view of an example building block 300 from one side,

Figure 3A is a cross-sectional view of the building block of Figure 3 along a section line C-C Figure 3B is a cross-sectional view of two building blocks of Figure 3 in stacked engagement, Figure 4A is a cross-sectional view of an example building block 400, and

Figure 4B is a cross-sectional view of two building blocks of Figure 4A in stacked engagement.

Description

[0108] An example building block 100 comprises a first side 120, a second side 140 and a peripheral portion 160 interconnecting the first side 120 and the second side 140. A plurality of connectors 122 is formed on the first side 120 and a plurality of connectors 142 is formed on the second side 140, as depicted in Figures 1 , 1 A, 1 B, 1 C and 1 D. [0109] A connector 122 on the first side has a first coupling axis X-X' defining a first coupling direction +X, as depicted in Figures 1 and 1 C. The connector 122 projects from a first surface 123 and extends away from the first surface 123 in the first coupling direction. The plurality of connectors 122 on the first side 120 cooperates to form a first connection means on a first surface 123 of the building block 100. The first connection means has a first connection axis defining a first connection direction, and the first surface 123 and the first connection means cooperate to define a first connection surface. The first connection means is to enter into mechanical coupled engagement with a corresponding building block having a corresponding connection means which is matched and compatible to the first connection means. When the building block and the corresponding building block are in mechanical coupled engagement with the first connection means of the building block 100 in mechanical coupled engagement with the corresponding connection means of the corresponding building block, the first connection surface of the building block 100 is in abutment contact with a corresponding connection surface of the corresponding building block and a releasable building block assembly or sub-assembly is formed. The first connection surface of the example building block is the first surface 123, which is on the first side of the building block.

[01 10] A connector 142 on the second side 140 has a second coupling axis Y-Y' defining a second coupling direction +Y, as depicted in Figures 1 A and 1 C. The connector 142 depends from a second surface 143 of the panel portion 124 and projects away from the second surface 143 to extend towards the second side 140 in the second coupling direction +Y. The plurality of connectors 142 on the second side 140 cooperates to form a second connection means on the second side 140 of the building block 100. The second connection means has a second connection axis defining a second connection direction, and the second connection means cooperate with the lower axial end of the peripheral portion, which is on the second side 140 of the building block 100, to define a second connection surface 145. The second connection means is to enter into mechanical coupled engagement with a corresponding building block having a corresponding connection means which is matched and compatible to the second connection means. When the building block 100 and the corresponding building block are in mechanical coupled engagement with the second connection means of the building block 100 in mechanical coupled engagement with the corresponding connection means of the corresponding building block, the second connection surface 145 of the building block 100 is in abutment contact with a corresponding connection surface of the corresponding building block and a releasable building block assembly or sub-assembly is formed. The second connection surface 145 of the example building block is a bottom surface of the building block defined by the lower axial end of the peripheral portion 160 which is distal to the first surface 123.

[01 1 1 ] The building block comprises a panel portion 124 and a peripheral portion 160 surrounding the panel portion. The panel portion has an upper panel surface 123 which is also the first surface 123 of the building block 100, and a lower panel surface 143 which is a second surface of the panel portion. The upper panel surface 123 and the lower panel surface 143 are parallel and opposite facing, and the axial extent between the upper panel surface 123 and the lower panel surface 143 defines the thickness, or more specifically the axial thickness, of the panel portion, the axial extent being measured with respect to the second connection direction of the building block. The axial extent of the panel portion is substantially constant and the panel portion has a substantially uniform thickness.

[01 12] The peripheral portion comprises a main peripheral wall 162 which depends downwardly from the upper panel surface 123. The main peripheral wall 162 surrounds the panel portion and extends axially between the first connection surface 123 and the second connection surface 145. The panel portion 124 and the peripheral portion 160 cooperate to define a main internal compartment 164 of the building block 100. The main peripheral wall 162 has a uniform axial extent with respect to the coupling directions to define a peripheral portion having a uniform thickness.

[01 13] The plurality of connectors 122, 142 is formed on the panel portion, with the connectors 122 on the first side 120 projecting away from the upper panel surface 123 and the connectors 142 on the second side 140 depended from the lower panel surface 143 and projecting downwardly towards the second connection surface 145.

[01 14] The connectors 122, 142 are arranged in an example connector matrix. The example connector matrix has a plurality of connector rows and a plurality of connector columns, with a connector row being orthogonal to a connector column. The connector matrix is arranged in the form of a regular matrix such that adjacent rows and adjacent columns of the matrix are at equal spacing. When adjacent rows and adjacent columns of the matrix are at equal spacing, adjacent rows and adjacent columns of the matrix have a constant pitch and a uniform separation distance defining the pitch. The term pitch herein means the separation distance between adjacent connector rows and/or adjacent connector columns unless the context requires otherwise. When connectors are distributed following a regular matrix, adjacent connectors in a row and adjacent connectors in a column have the same separation distance defined by the pitch of the regular matrix. The example connector matrix is optional disposed such that an outermost connector row that is closest to a portion of a corresponding outer peripheral wall of the building block which is parallel to the outermost connector row is at half pitch, which means the separation distance between the connector row and the corresponding outer peripheral wall, referred to as a row wall, is at half of the separation distance between adjacent connector rows. Likewise, an outermost connector column that is closest to a portion of a corresponding outer peripheral wall of the building block which is parallel to the outermost connector column is at half pitch, which means the separation distance between the connector column and the corresponding outer peripheral wall, referred to as a column wall, is at half of the separation distance between adjacent connector columns.

[01 15] The connectors 122 on the first side 120 of the building block 100 are distributed in a square matrix. More specifically, the example plurality of the connectors 122 on the first side 120 of the building block 100 is distributed in the form of a square matrix having four rows and four columns, with adjacent connectors in a row and adjacent connectors in a column having equal spacing and at a constant separation distance equal to the matrix pitch. Likewise, the connectors 142 on the second side 140 of the building block 100, or the lower panel surface 143, are distributed in a square matrix. More specifically, the example plurality of the connectors 142 on the second side 140 of the building block 100 is distributed in the form of a square matrix having four rows and four columns, with adjacent connectors in a row and adjacent connectors in a column having an equal spacing or a constant separation distance.

[01 16] The connectors 122 on the first side of the building block 100 and the connectors on the second side 140 of the building block 100 are connection axes aligned. When the connectors 122 on the first side of the building block 100 and the connectors on the second side 140 of the building block 100 are connection axes aligned, the first connection axis and the second connection axis are coaxial or aligned. The connectors 122, 142 are coupling axes aligned connectors such that a connector 122 on the first side has a corresponding connector 142 on the second side having its coupling axis aligned with the coupling axis of the connector 122 to form a connector pair. The connector pair has a center axis Z-Z', which is coaxial or aligned with both the first connection axis and the second connection axis. A connector 122 on the first side and a connector 142 on the second side which are coupled axes aligned are referred to as an axes-aligned connector pair herein. The axes-aligned connector pairs are interconnected by the panel portion 124 and formed on a single panel.

[01 17] The panel portion 124 has a square boundary delimited by a peripheral wall which extends along the square boundary. The peripheral wall includes an inner peripheral wall which defines the internal compartment 164 of the building block and an outer peripheral wall which surrounds the inner peripheral wall. The outermost connector column which is closest to a portion of a corresponding outer peripheral wall of the building block that is parallel to the outermost connector column is at half pitch. An outermost connector row which is closest to a portion of a corresponding outer peripheral wall of the building block that is parallel to the outermost connector row is at half pitch. When an outermost connector row of a building block has a half pitch to the outer peripheral wall, the outermost connector row of the building block and an outermost connector row or column of a corresponding building block having its corresponding outer peripheral wall in abutment with the outer peripheral wall of the building block is at a full pitch.

[01 18] While the example building block has a square panel portion and the connector matrix is a square matrix of 4x4, the panel portion need not be square and the connector matrix may be a non-square matrix.

[01 19] For example, the panel portion may be square and the connector matrix may be a 3x3, 5x5, 6x6, 7x7, 8x8 or other sizes. For example, the panel portion may be rectangular and the connector matrix may be a 1x2, 1x3, 1x4, 2x3, 2x4, 2x5, 3x4, 3x5, 3x6, 3x7, 4x5, 4x6, 4x7, ... , or any other order without loss of generality. In some embodiments, the panel portion has a polygonal boundary having three sides or more than four sides without loss of generality, and the sides may be of equal or unequal lengths.

[0120] In some embodiments, the panel portion may have a circular boundary and the connectors on a side is arranged in rows of concentric circles with equal spacing between connectors 122, 142 in a circular row and adjacent circular rows. The connectors 122, 142 on the first side and the second side are correspondingly disposed so that a connector 122 on the first side has a corresponding connector 142 on the second side which is coupling axis aligned with the connector 122 on a first side.

[0121 ] The example connector 122 on the first side is a male connector having a first coupling axis and a first coupling direction which is orthogonal to the first surface 123. The male connector 122 comprises a protrusion which projects away from the first surface 123 and extends in the coupling direction +X to define the axial extent or the height H of the connector above the first surface 123. The coupling direction is along the coupling axis X-X' and is orthogonally away from the first side 120 and the second side 140 of the building block. The protrusion is an annular protrusion having axis symmetry about its center axis, which is also the coupling axis X-X'.

[0122] The protrusion is hollow and comprises a head portion and a neck portion. The head portion comprises a bulged portion which is axially elevated from the first surface 123. The bulged portion has a maximum radial extent at an axial level, referred to as a maximum radial extent level, defining a maximum radial plane. The bulged portion tapers to narrow as it extends axially away from the maximum radial plane, both in axial directions towards and away from the first surface 123. The bulged portion of the example connector 122 follows a convex curve to taper and has a convexly curved radial profile. In some embodiments, the bulged portion has a rippled radial profile having two tapered axial ends, and the portion of the bulged portion intermediate the two tapered ends may be cylindrical or have a partial spherical profile. In some embodiments, the bulged portion follows a substantially constant slope to taper.

[0123] The neck portion comprises a narrowed portion in abutment with the first surface 123. The neck portion tapers to narrow as it extends away from the head portion to join the first surface 123. The neck portion of the example connector 122 follows a convex curve to taper and has a convexly curved radial profile. In some embodiments, the neck portion follows a substantially constant slope to taper.

[0124] The protrusion of the male connector 122 is a hollow protrusion comprising an interior compartment. The interior compartment is defined by a shell-like structure which defines the shape and dimensions of the male connector 122. The shell-like structure comprises a peripheral wall which extends in a peripheral direction to define an internal bore 127 of the protrusion and a ceiling wall which spans radially across the internal bore to form the interior compartment in cooperation with the peripheral wall. The internal bore and an internal cavity defined by the internal bore extends between the first surface and the free axial end of the protrusion. The example internal bore of the connector 122 extends through a substantial portion of the protrusion. In this example, the internal bore 127 has an axial extent of more than 60% of the axial extent of the protrusion above the first surface 123, and an upper axial end of the internal bore 127 is at an axial level above the level of the maximum radial plane of the bulged portion. The axial extent of the internal bore 127 can be between 10% and 100% of the axial extent of the protrusion, for example, in percentage terms, at 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges. In general, a range between 30-70% has been found to provide a good balance between rigidity, resilience and spatial efficiency. When the axial extent of the internal bore is 100% of the axial extent of the protrusion, the internal bore is a through bore. Therefore, the internal bore extends to stop below the bulged portion in some embodiments, extends axially up to or beyond the axial level of the bulged portion in other embodiments, and extends through the protrusion to form a through bore which extends through the protrusion in yet other embodiments. The example internal bore 127 is a cylindrical bore having a constant radial extent in the axial direction. In some embodiments, the internal bore may follow the shape or profile of the top axial end of a protrusion for receiving that portion when in coupled engagement.

[0125] The example connector 142 on the second side is a female connector having a second coupling axis Y-Y' and a second coupling direction +Y which is orthogonal to the second connection surface 145. The second connection surface 145 is defined by the lower axial end of the peripheral portion 160 and the second coupling axis Y-Y' is opposite to the first coupling axis X-X'.

[0126] The female connector 142 comprises a receptacle for making snap engagement with a matched corresponding male connector. The receptacle depends from the second surface 143 and extends axially downwards in the second coupling direction +Y from the second surface 143 towards the second connection surface 145. The second coupling direction +Y is along the second coupling axis and is opposite to the first coupling direction +X. The receptacle is an annular receptacle having axis symmetry about its center axis which is the coupling axis Y-Y'.

[0127] The receptacle comprises a receptacle compartment which is defined by a receptacle peripheral wall. The receptacle peripheral wall extends axially between the lower panel surface 143 and the second connection surface 145 to define the receptacle compartment. The peripheral wall is an annular peripheral wall which projects axially towards the second connection surface 145. The peripheral wall includes an inner peripheral wall which is shaped and dimension to define an annular receptacle compartment for snap reception of a matched and compatible male connection portion. The peripheral wall has a thickness which is optionally comparable to the thickness of the panel.

[0128] The example receptacle comprises a first receptacle portion and a second receptacle portion. The second receptacle portion is at an axial level which is intermediate the axial level of the first receptacle portion and the axial level of the lower panel surface 143. The first receptacle portion and the second receptacle portion are in series and are aligned on a center axis which is also the second coupling axis. The example receptacle and the receptacle peripheral wall has a lower axial end defining an entry end of the receptacle. The receptacle entry end in this example is flush with the second connection surface 145, although the lower axial end may stop short of the second connection surface 145 in some embodiments.

[0129] The first receptacle portion is at a lower axial end of the receptacle which is a distal axial end to the lower panel surface 143 and includes a receptacle entry. The first receptacle portion is a neck receptacle portion for closely fitted reception of the neck portion of a corresponding male connector. The first receptacle portion tapers to narrow as it extends towards the distal axial end to define a tapered neck receptacle portion which is matched with the tapered neck portion of the corresponding male connector to facilitate snap connection with the tapered neck portion. The neck receptacle portion of the example connector 142 follows a concave curve to taper and has a concavely curved radial profile to match the profile of a neck portion of a corresponding male connector. In some embodiments, the neck portion follows a substantially constant slope to taper.

[0130] The second receptacle portion extends axially between the lower panel surface 143 and the first receptacle portion. The second receptacle portion is a head receptacle portion for closely fitted reception of the head portion of a corresponding male connector. The second receptacle is a bulged receptacle which is shaped and dimensioned to match with the shape and dimensions of the bulged head portion of a corresponding head portion of a corresponding male connector to facilitate snap connection therewith. The head receptacle portion of the example connector 142 follows a concave curve to taper and has a concavely curved radial profile. In some embodiments, the head receptacle portion has a rippled radial profile having two tapered axial ends or a sloping radial to taper to match the profile of a neck portion of a corresponding male connector.

[0131 ] In this example, the neck receptacle portion is shaped and dimensioned to match the shape and dimensions of the neck portion of the male connector 122, the head receptacle portion is shaped and dimensioned to match the shape and dimensions of the bulged portion of the male connector 122, and the axial separation between the head receptacle portion and the neck receptacle portion is matched with, that is, or corresponds to, the axial separation between the bulged head portion and the narrowed neck portion of the male connector 122. The connector 122 and the connector 142 in this example have matched and compatible engagement portions and are therefore a matched pair of snap connectors. When two building blocks 100 are peripheral wall aligned and a first building block 100 is stacked on a second building block 100 with their respective first connection surfaces facing the same direction, the connectors 122 on the first building block 100 will enter into snap engagement with the connectors 142 on the second building block 100 when the two building blocks are pressed against each other to enter into snap engagement.

[0132] In this example, the receptacle continues into the panel portion and a portion of the receptacle is formed inside the panel portion. More specifically, the second receptacle portion projects axially to continue into the panel portion and the panel portion forms a portion or part of the receptacle compartment. [0133] A bridging portion interconnecting the internal bore 127 and the receptacle compartment 147 is formed on the panel portion. The bridging portion includes a bridging bore 137 which extends axially through the panel portion to interconnect the receptacle compartment 147 of the receptacle of the female connector 142 and the internal bore 127 of the protrusion of the male connector 122. The example bridging bore 137 comprises a first bore portion which is a serial continuation of the internal bore 127 and a second bore portion which is a serial continuation of the receptacle compartment 147. The first bore portion conjoins the internal bore and has a smaller radial extent than the second bore portion which conjoins the receptacle compartment. The bridging bore 137 is defined between two parallel planes, namely a first plane which is coplanar with the lower panel surface 143 and a second plane which is coplanar with the upper panel surface 123. The first bore portion joins the second bore portion at a third plane which is parallel to and between the first plane and the second plane. The second bore portion extends between the first plane to the third plane and has a radial extent which is the same as the radial extent of the head receptacle portion. The second bore pore has an axial height H1 , which defines an additional height of the receptacle which is inside the panel portion 124 and is in continuation with the receptacle portion of the connector 142.

[0134] With the continuation of the second receptacle portion into the panel portion, the thickness of the building block can be reduced to meet thickness requirements.

[0135] The thickness of the building block 100 is a sum of the axial extent of the protrusion, the axial extent of the receptacle portion of the connector 142, and the axial extent of the panel portion. Where the building block is to be stack connectable with a corresponding building block having the same male connectors 122, so that corresponding connection surfaces on the corresponding building block are in flush abutment contact, the thickness of a conventional stackable block is two times the axial extent of the protrusion 122 plus the thickness of the panel portion. In other words, the minimum thickness of the peripheral portion must be the axial extent of the protrusion 122 plus the thickness of the panel portion. The term "flush abutment" here means a second connection surface of one building block 100 and a second connection surface of another building block 200 are in abutment contact, with the second connection surface resting evenly and square on the first connection surface or with the first connection surface resting evenly and square on the second connection surface.

[0136] With the incorporation of the bridging portion, the top axial end of the protrusion can project into the panel portion or the internal bore 127 and stay therein while the corresponding connection surfaces of the engaged building blocks are in flush abutment, and the thickness of the building block is no longer bound by the conventional restrictions. For example, the axial extent of the receptacle can be smaller than the axial extent of the protrusion. Furthermore, as the axial extent of the receptacle is no longer bound by the lower panel surface, the protrusion can have a larger tolerance in respect of its axial extent.

[0137] In some embodiments, the receptacle is inside the bridging bore or inside the panel portion. For example, the head receptacle portion or portion thereof can be inside the panel portion. For example, the neck receptacle portion or a portion thereof can be inside the panel portion to enhance compactness.

[0138] An example building block 200 comprises a first side 220, a second side 240 and a peripheral portion 260 interconnecting the first side 220 and the second side 240. A plurality of connectors 222 is formed on the first side 220 and a plurality of connectors 242 is formed on the second side 240, as depicted in Figures 2, 2A, 2B, 2C and 2D.

[0139] In this example, the connector 222 on the first side 220 has a rounded connector head, with a dome-shaped ceiling wall spanning across the internal bore 227 to cooperate with the peripheral wall to form the interior compartment of the protrusion, and the connector 242 comprises a receptacle having a receptacle compartment which is shaped to correspond to the rounded connector head. Except for the aforesaid differences, the building block 200 is identical or equivalent to the building block 100 and the description on and in relation to the building block 100 is incorporated herein by reference and to apply mutatis mutandis unless the context requires otherwise, and with corresponding numerals increased by 100.

[0140] The male connector 222 of the building block 200 has a first axial extent above the first surface 223 defining the height of the male connector 222 or its protrusion. The female connector 242 of the building block 200 has a second axial extent below the second surface 243 defining the depth of the peripheral wall of the receptacle. The depth of the peripheral wall of the receptacle is smaller than the height of the male connector 222 or its protrusion.

[0141 ] When two building blocks 200 are peripheral wall aligned and a building block 200 is stacked on another building block 200 with their respective first connection surfaces 223 facing the same direction, the connectors 222 on the building block 200 will enter into snap engagement with the connectors 242 on the other building block 200 when the two building blocks are pressed against each other to enter into snap engagement.

[0142] When the two building blocks 200 are in snap engagement so that the second connection surface 245 is in flush and even abutment with the first connection surface 223 of the other building block, the rounded top end of the protrusion of the connector 222, or a portion thereof, is received inside the panel portion, or more specifically inside the bridging bore 237.

[0143] An example building block 300 comprises a first side 320, a second side 340 and a peripheral portion 360 interconnecting the first side 320 and the second side 340. A plurality of connectors 322 is formed on the first side 320 and a plurality of connectors 342 is formed on the second side 340, as depicted in Figures 3, 3A and 3B.

[0144] In this example, the lower panel surface 343 is flush with the second connection surface 345 and the entire receptacle is formed inside the panel portion 324. A peripheral groove is formed on the panel portion 324 to surround the entry end of the receptacle. The receptacle has an axial height H3, which is smaller than the height H of the connector 322 above the first surface 323. Where the building block 300 is to be stack connected with a corresponding building block having the same male connectors 322, so that corresponding connection surfaces on the corresponding building block are in flush abutment contact, the top axial end of the protrusion will project into the panel portion 324 and into the internal bore 327 of the protrusion and stay therein while the corresponding connection surfaces of the engaged building blocks are in flush abutment, and the thickness of the building block can be further reduced. Except for the aforesaid differences, the building block 300 is identical or equivalent to the building block 200 and the description on and in relation to the building block 200 is incorporated herein by reference and to apply mutatis mutandis unless the context requires otherwise, and with corresponding numerals increased by 100. This configuration substantially reduces the depth of the receptacle and further shrink the axial extent or thickness of the building block 200. In some embodiments, the neck receptacle portion may be at an axial level proximal the second surface and can be above or below the second surface. In some embodiments, neck receptacle portion or a portion thereof is inside the panel portion. In some embodiments, the head receptacle portion or a portion thereof is inside the panel portion or is inside the internal bore of the protrusion portion.

[0145] An example building block 400 comprises a first side 420, a second side 440 and a peripheral portion 460 interconnecting the first side 420 and the second side 440. A plurality of connectors 422 is formed on a first panel portion on the first side 420 and a plurality of connectors 442 is formed on a second panel portion on the second side 440, as depicted in Figures 4A and 4B.

[0146] In this example, the connectors 442 on the second side 440 are formed inside the second panel portion 444. The second panel portion 444 has a lower panel surface which is and defines the second connection surface 445 of the building block 400, and an upper panel surface 446 which is a second surface of the panel portion. The upper panel surface 446 and the lower panel surface 445 are parallel and opposite facing, and the axial extent between the upper panel surface 446 and the lower panel surface 445 defines the thickness, or more specifically the axial thickness, of the second panel portion 444, the axial extent being measured with respect to the second connection direction of the building block. The axial extent of the second panel portion is substantially constant and the second panel portion has a substantially uniform thickness. A polarity of bore is formed on the second panel portion 444 to define the entry end of the receptacle. The receptacle has an axial height H4, which is larger than the thickness of the second panel portion 444 and smaller than the height H of the connector 422 above the first surface 423. Except for the aforesaid differences, the building block 400 is identical or equivalent to the building block 200 and the description on and in relation to the building block 200 is incorporated herein by reference and to apply mutatis mutandis unless the context requires otherwise, and with corresponding numerals increased by 100.

[0147] While the disclosure has been described with reference to examples and embodiments, the examples and embodiments are not meant to be restrictive and should not be used to limit the scope of disclosure.

[0148] While the disclosure has made reference to various embodiments, the embodiments are for example and should not be used to limit restrict the scope of the disclosure.

[0149] For example, the example building blocks herein are toy building blocks for toy or toy-like applications and the building block assemblies are toy or toy-like building block assemblies. However, the building blocks herein can also be non-toy building blocks such as machine building blocks, construction building blocks such as tiles or bricks, and/or other industrial building blocks and the building block assemblies are modular built machines or machine parts, modular built structures, modular built structure parts, modular built structural parts, modular built fixture and/or fixture parts and/or fixture sub-assemblies.

[0150] When used for toy applications as toy assemblies, the component building blocks have a typical radial extent (or width, or lateral extent) of between 1 cm and 15cm and a typical axial extent (or thickness) or between 0.3mm for a miniature block to 5cm. For example, the radial extent can be, in units of cm, 1 for a miniature block, 1 , 1 .5, 2, 2.5, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 1 1 , 1 1 .5, 12, 12.5, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, or more for a mega block, or a range or any ranges formed by a selected combination of any of the aforesaid values as limits of a range or limits of ranges. For example, the axial extent can be, in units of cm, 1 for a miniature block, 1 , 1 .5, 2, 2.5, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, or more for a mega block, or a range or any ranges formed by a selected combination of any of the aforesaid values as limits of a range or limits of ranges.

[0151 ] When for industrial uses, for example for modular construction of machines, buildings, structures, parts, the aforesaid values may be scaled up, in unit of times, by 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 1 10, 120, or a range or any ranges formed by a selected combination of any of the aforesaid values as limits of a range or limits of ranges; and the component building blocks may be made of strong thermoplastics, carbon fibres, fibre glass, or metals, or other mouldable materials, having a high rigidity and a small degree of resilience.

[0152] While assemblies of the building blocks have been described with reference to snap engagement or snap connection and snap connectors, the building blocks may be joined or connected by other press-fit mechanisms or methods without loss of generality.

[0153] While the example connectors described and depicted herein are snap connectors adapted for making snap-fit engagement, a connector herein can be a "press-fit" connector for making press-fit engagement or a "friction-fit for making press-fit engagement unless the context requires otherwise.

[0154] In general, a snap-fit connector comprises an engagement portion having snap-fit mating features. The terms "snap", "snap fit", and "snap-fit", are interchangeably used herein unless the context requires otherwise. The terms "fastener" and "connector" are also interchangeably used herein unless the context requires otherwise. In this description and specification, and when in relation to a connector or an engagement portion having a coupling axis, the terms "closely-fitted engagement" and "coupled engagement" are interchangeable, the axial direction is with respect to the coupling axis and the axial direction is along the coupling axis, and the radial direction is with respect to the coupling axis and the radial extent is in the radial direction, unless the context requires otherwise.

[0155] The words "first", "second", "third", "fourth", etc. are generic terms for ease of reference only and are not intended for indicate priority, order or sequence unless the context requires otherwise or specifies otherwise. Where there are conflicts in relation to the aforesaid generic terms, the conflicts are to resolve to give a meaning which is reasonable for interpretation where possible.

[0156] While singular and plural terms are used herein, a singular term may apply mutatis mutandis to a plural situation and a plural term may apply mutatis mutandis to a single situation where the context permits or requires. Table of numerals

Claims

A building block comprising a main body, a panel portion on the main body, a first surface on one side of the panel portion, a second surface on a second side of the panel portion, the first surface and the second surface being opposite facing surfaces, and one connector pair or a plurality of connector pairs; wherein the connector pair comprises a male connector having a first coupling axis defining a first coupling direction along the first coupling axis, and a corresponding female connector having a second coupling axis defining a second coupling direction along the second coupling axis; wherein the first coupling axis and the second coupling axis are axes aligned and coaxial, and the second coupling direction is opposite to the first coupling axis; wherein a bridging bore interconnecting a male connector and a corresponding female connector of a connector pair is formed on the panel portion; wherein the male connector comprises a hollow protrusion portion having an interior compartment, and the female connector comprises a receptacle portion having an inner peripheral wall defining a receptacle compartment; and wherein the interior compartment, the bridging bore and the receptacle compartment cooperate to form an internal bore extending between the male connector and the female connector.

The building block according to Claim 1 , wherein the male connector projects from the first surface and extends in a first projection direction away from the first surface, the first projection direction being defined by a first projection axis which is coaxial with the first coupling axis, and wherein the female connector projects from the second surface and extends in a second projection direction away from the second surface, the second projection direction being defined by a second projection axis which is coaxial with the second coupling axis.

The building block according to Claims 1 or 2, wherein the male connector has a first axial extent, the first axial end being measured between a free axial end of the protrusion portion and the first surface in the first coupling direction, wherein the receptacle portion has a second axial extent, the second axial extent being measured between a free axial end of the receptacle portion and the second surface in the second coupling direction; and wherein the first axial extent is larger than or equal to the second axial extent.

The building block according to Claim 3, wherein the second axial extent is between 15%- 95% of the first axial extent, including, in percentage terms, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 of the first axial extent, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges. The building block according to Claims 3 or 4, wherein the interior compartment has a third axial extent, and the third extent is between 10% and 100% of the first axial extent, including, in percentage terms, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

The building block according to any of Claims 3 to 5, wherein the protrusion portion comprises a neck portion, the neck portion being a narrowed portion which is in abutment with or proximal the first surface, and the receptacle portion comprises a neck receptacle portion, the neck receptacle portion defining a narrowed entry aperture to the receptacle portion; and wherein the neck receptacle portion is at an axial depth below the second surface, the axial depth being smaller than the first axial extent.

The building block according to Claim 6, wherein the axial depth is a fraction of the first axial extent, and the fraction is between 15%-95% of the first axial extent, including, in percentage terms, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 of the first axial extent, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

The building block according to any of Claims 3 to 5, wherein the protrusion portion comprises a neck receptacle portion and the neck receptacle portion or a portion thereof is inside the panel portion.

The building block according to any preceding Claim, wherein the main body comprises a peripheral portion, the peripheral portion including a peripheral wall extending axially between a first connection surface and a second connection surface, and wherein the peripheral wall has a fourth axial extent, and the fourth axial extent is between 20% and 100% of the first axial extent, including, in percentage terms, 20, 20, 30, 40, 50, 60, 70, 80, 90, 100, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

0. The building block according to any preceding Claim, wherein the male connector comprises a peripherally extending first peripheral wall which defines the interior compartment of the protrusion portion, and the receptacle portion of the female connector comprises a peripherally extending second peripheral wall, the second peripheral wall including the inner peripheral wall which defines the receptacle compartment and an outer peripheral wall which surrounds the inner peripheral wall; and wherein the first peripheral wall and the second peripheral wall are coaxially aligned.

1 1 . The building block according to Claim 10, wherein the first peripheral wall projects from the first surface of the panel portion and extends in the first coupling direction, and the second peripheral wall depends from the second surface of the panel portion and extends in the second coupling direction.

12. The building block according to Claims 10 or 1 1 , wherein the second peripheral wall forms a tubular portion depending from the second surface and extending in the second coupling direction to approach a second connection surface.

13. The building block according to any preceding Claim, wherein the interior compartment, the bridging bore and the receptacle compartment are coaxial and in fluid communication. 14. The building block according to any preceding Claim, wherein the protrusion portion comprises a bulged portion, the bulged portion having a maximum radial extent plane at a maximum radial extent level above the first surface, and wherein the receptacle portion has a bulged receptacle portion, the bulged receptacle portion having a maximum radial clearance plane at a maximum radial clearance level below the second surface; and wherein the maximum radial clearance level is a second fraction of the maximum radial extent level.

15. The building block according to Claim 14, wherein the second fraction is between 20% and 95%, including, in percentage terms, 20, 20, 30, 40, 50, 60, 70, 80, 90, 95, or a range or any ranges formed by a combination of any of the aforesaid values as limits of a range or limits of ranges.

16. The building block according to Claim 14, wherein the bulged receptacle portion or a portion thereof is inside the panel portion or the bridging bore.