WO2024133852A1

WO2024133852A1 - Tube connector for modular construction system

Info

Publication number: WO2024133852A1
Application number: PCT/EP2023/087538
Authority: WO
Inventors: Janus Juul Rasmussen; Flemming Pedersen; Steffen ISGREEN
Original assignee: Lego A/S
Priority date: 2022-12-22
Filing date: 2023-12-22
Publication date: 2024-06-27
Also published as: WO2024133846A1; WO2024133861A1

Abstract

A tube connector (20) for a modular toy construction system (10), wherein said modular toy construction system (10) comprises a first construction element (11), and a second construction element (12), wherein the first construction element (11) comprises a cylindrical connector (100) having a cylindrical outer surface (110), wherein the second construction element (12) is provided with the tube connector (20), wherein the tube connector is configured for coupling to the cylindrical connector (100) in a press fit, wherein the tube connector (20) comprises a tubular wall (30) surrounding a cylindrical opening (31) and having a cylindrical inner surface (32) formed to fit over the cylindrical outer surface (110) of the cylindrical connector (100), wherein the cylindrical inner surface (32) is provided with two and only two pressure surfaces (40) protruding from the inner cylindrical surface (32), which pressure surfaces (40) are configured for providing a pressure against the cylindrical outer surface (110) of the cylindrical connector (100), and where no other part of the cylindrical inner surface (32) provides pressure to the cylindrical outer surface (110) of the cylindrical connector (100), when the tube connector (20) and the cylindrical connector (100) have been connected to each other.

Description

TUBE CONNECTOR FOR MODULAR CONSTRUCTION SYSTEM

The present invention relates to a connector for connecting two items, such as two elements of a modular construction system. More specifically the invention relates to a tube connector for modular construction systems. More specifically the invention relates to a tube connector for a modular toy construction systems

Background of the invention

Tube connectors for modular toy construction systems are known in the art

Such tube connector are configured for connecting a first construction element having a cylindrical connector and a second construction element having a tube connector according to the invention in a press fit connection. The cylindrical connector on the first construction element comprises a cylindrical outer surface. The tube connector comprises a tubular wall surrounding a cylindrical opening for receiving the cylindrical connector, and further has a cylindrical inner surface formed to fit over the cylindrical outer surface of the cylindrical connector.

Further, the cylindrical inner surface of the tube connector comprises four planar pressure surfaces, equidistantly located along a perimeter of the cylindrical inner surface of the tubular wall of the tube connector. The cylindrical inner surface and the planar pressure surfaces of the tube connector are dimensioned such that they provide the pressure fit on the cylindrical outer surface of the cylindrical connector, when the tube connector is pressed over the cylindrical connector. Thereby, the tubular wall of the tube connector and/or the material of the cylindrical connector will deform, where the four planar pressure surfaces press against the cylindrical outer surface of the cylindrical connector.

For example such connectors may be made in ABS plastic, in an injection moulding process. It has shown that the function and quality of the connections between tube connectors and cylindrical connectors are very sensitive to the type of material used for the making the connection, and to the dimensions, such as material thickness of the construction element to which they form part, etc., and that this puts demands for extreme tolerances in making of the tube connectors. There is thus a need for a tube connector which lowers the requirements on the tolerances in production of the construction element with tube connectors.

Thus, in order to produce a constant quality, for example the clutch power between the tube connector and the cylindrical connector, of the connection between tube connectors to complementary cylindrical connectors, for each new construction block design, a specifically dimensioned tube connector needs to be designed. Designing each time such a connection is time consuming.

Summary of the invention

It is therefore an object of the invention to provide a tube connector, which can more easily be adapted to be formed in various plastics, and for variously shaped and dimensioned construction elements of modular construction systems.

In a first aspect, the objects of the invention are achieved by a tube connector for a modular toy construction system, wherein the modular toy construction system comprises

- a first construction element , and

- a second construction element, wherein the first construction element comprises a cylindrical connector having a cylindrical outer surface, wherein the second construction element is provided with the tube connector, wherein the tube connector is configured for coupling to the cylindrical connector in a press fit, wherein the tube connector comprises a tubular wall surrounding a cylindrical opening and having a cylindrical inner surface formed to fit over the cylindrical outer surface of the cylindrical connector, wherein the cylindrical inner surface of the tube connector is provided with two and only two pressure surfaces protruding from the inner cylindrical surface, which pressure surfaces are configured for providing a pressure against the cylindrical outer surface of the cylindrical connector, and where no other part of the cylindrical inner surface provides pressure to the cylindrical outer surface of the cylindrical connector, when the tube connector and the cylindrical connector have been connected to each other.

This two-surface pressure contact allows for optimal material usage in order to obtain the desired strain/stiffness of the press fit connection and increased interface robustness. This is obtained over a wide range of plastics and dimensioning.

Preferably, two pressure surfaces are identically shaped. Alternatively, the two pressure surfaces are made different from each other, dependent on the shape, material or other characteristics of the construction element and tube connector, such that qualities, such as the clutch power between the tube connector and the cylindrical connector remain within requirements.

In an embodiment, each of the two pressure surfaces are configured such that in at least an axial direction of the tube connector, the pressure surface is formed substantially parallel with the cylindrical inner surface.

In a further embodiment, each of the two pressure surfaces are configured such that in at least an axial direction of the tube connector, the pressure surface is formed substantially parallel with the cylindrical outer surface of the cylindrical connector, when the tube connector and the cylindrical connector have been connected to each other.

In a further embodiment, a rounded transition surface is provided between the pressure surface and a front end surface of the tube connector for each of the two pressure surfaces. In an embodiment thereof, at least a first portion of the rounded transition surface is configured for guiding the cylindrical outer surface of the cylindrical connector onto the pressure surface, during the act of connecting the tube connector to the the cylindrical connector

The first portion of the rounded transition surface is adjacent to the pressure surface. A transition is provided between the first portion of the rounded transition surface and the pressure surface. This transition is preferably smooth.

The rounded transition surface further comprises a second portion, which is formed adjacent to first portion and adjacent to the front end surface. The second portion of the rounded transition surface is further formed between the front end surface and the first portion of the rounded transition surface. A transition is provided between the first portion of the rounded transition surface and the second portion of the rounded transition surface. This transition is preferably smooth.

The second portion of the rounded transition surface serves as a catch surface, configured to provide an entrance into the cylindrical opening defined by the cylindrical inner surface of the tube connector.

The first portion of the rounded transition surface constitutes an inlet surface to guide the cylindrical outer surface of the cylindrical connector onto the pressure surface. Thus, the first portion is inclined relative to the pressure surface to provide a ramp for guiding the cylindrical outer surface of the cylindrical connector onto the pressure surface. Thus, the inlet surface configuration formed by the first portion prevents or at least reduces damage to the pressure surface.

In a further embodiment, for each of the two pressure surfaces, an undercut is provided between the pressure surface (40) and the bottom surface of the tube connector. Thereby a length of each pressure surface extends over a fraction of the overall length of the inner cylindrical surface of the tubular wall of the tube connector in the axial direction of the tube connector.

In an embodiment thereof, for each of the two pressure surfaces, the surface defining the undercut (60) is adjacent to the respective pressure surface (40).

In a further embodiment thereof, a transition is provided between the pressure surface and the undercut.

In a further embodiment, this transition is smooth.

In a further embodiment, the undercut transitions into the cylindrical inner surface of the tube connector. Preferably, this transition is smooth.

This has the effect that a spring-back effect of the connection between the cylindrical connector and the tube connector potentially induced by the pressure surfaces is reduced or eliminated.

In a further embodiment, for each of the two pressure surfaces, a side surface is formed on both sides of the pressure surface in a direction perpendicular to an axial direction of the tube connector.

In an embodiment thereof, each of the side surfaces transitions into the cylindrical inner surface of the tube connector.

In a further embodiment, when the tube connector and the cylindrical connector have been connected to each other, a clearance surrounds the protrusion on which the pressure surface is formed.

In a further embodiment, for each of the two pressure surfaces, when tube connector and the cylindrical connector have been connected to each other, the pressure provided by the protruding pressure surface provides a deformation of at least a portion of the cylindrical connector. In an embodiment thereof, the deformation of at least a portion of the cylindrical connector (100) is a local deformation of the cylindrical outer surface (110) of the cylindrical connector.

In an embodiment, the pressure surface is configured to provide a local deformation of a connector surface of the first connector.

By local deformation of a connector surface is meant a deformation which only occurs in the immediate vicinity of the location, where the pressure surface on the island contacts and presses on and/or into the connector surface.

Local deformation may provide a press fit/pressure fit/ interference fit without any substantial deformation of the rest - or major part - of the cylindrical outer surface of the cylindrical connector. Local deformation may further provide an interference or pressure fit without any substantial deformation of the cylindrical inner surface of tube connector.

In an embodiment, the two pressure surfaces are located diametrically across from each other on the cylindrical inner surface of the tubular wall of the tube connector.

In a further embodiment of any of the previously mentioned embodiments, each of the two pressure surfaces has a length in the axial direction of the tube connector, and a width in a direction perpendicular to the axial direction of the tube connector.

The length of each of the two pressure surfaces in the axial direction of the tube connector is non-zero.

The width of each of the two pressure surfaces in a direction perpendicular to the axial direction of the tube connector is non-zero.

In an embodiment, each of the two pressure surfaces are rectangular. In an embodiment, a width of each of the pressure surfaces extends over 5-60°, such as 20-50° of the cylindrical inner surface of the tube connector.

In an embodiment, the cylindrical inner surface is provided with a guide surface configured to provide contact with the cylindrical outer surface of the cylindrical connector without providing a deformation of the cylindrical outer surface of the cylindrical connector or the tubular wall.

Guide surfaces are dimensioned to provide a minimum of clearance between tube connector guide surfaces and the cylindrical outer surface of cylinder connectors to ensure positioning and grid compatibility without impacting functionality.

In a further embodiment thereof, the guide surface is planar.

In an embodiment, the guide surface extends from a front end surface of the tube connector to a bottom surface of the tube connector.

In a further embodiment, a width of guide surface extends over 10-45°, such as15- 30° of the cylindrical inner surface of the tube connector.

In a further embodiment, the tube connector comprises two guide surfaces.

In a further embodiment thereof, the two guide surfaces are located diametrically across from each other on the cylindrical inner surface of the tubular wall of the tube connector.

In a further embodiment thereof, the two guide surfaces are formed at 90° from the two pressure surfaces on the cylindrical inner surface of the tubular wall of the tube connector.

In a second aspect, the objects of the invention are achieved by a modular construction system comprising

- a first construction element, and - a second construction element, wherein the first construction element comprises a cylindrical connector having a cylindrical outer surface, and wherein the second construction element is provided with the tube connector according to any one of the embodiments of the first aspect of the invention.

In the context of the present invention, the term “smoothly transitioning” or “transitioning smooth” or “smooth transition” should be understood such that the transition between two surfaces, for example the pressure surface and the inlet surface, has a well-defined tangent in all locations in a direction parallel to the coupling direction. The transition is tangential. This means that there are no separating edges between the surfaces.

It should be emphasized that the term "comprises/comprising/comprised of' when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Brief description of the drawings

In the following, the invention will be described in greater detail with reference to embodiments shown by the enclosed figures. It should be emphasized that the embodiments shown are used for example purposes only and should not be used to limit the scope of the invention.

Fig. 1A, in a perspective view, shows a set of prior art modular construction elements of a modular construction system, the construction elements having complementary coupling means in the form of cylindrical connectors and recesses;

Fig 1 B shows the construction elements of Fig. 1A in an end view; Fig. 1 C, in a bottom view, shows a prior art construction element with recesses for receiving and coupling to the cylindrical connectors;

Fig. 1 D shows a section, A-A, through the set of construction elements of Fig. 1C.

Fig. 2A shows a set of prior art modular construction elements, a first element, and a second element, where the first and second construction elements are disassembled from each other, the construction elements having complementary coupling means in the form of cylindrical connector and a prior art tube connector;

Fig. 2B shows a bottom view of the second construction element of Fig 2A, including a prior art tube connector configured for connecting to a cylindrical connector provided on the first construction element shown in Fig. 2A;

Fig. 3, in a perspective view, shows a set of modular construction elements, a first element, and a second element,, the construction elements having complementary coupling means in the form of cylindrical connector and a new tube connector according to the invention, and where the cylindrical connecter is a closed knob;

Fig. 4 is a bottom view of the modular construction elements of Fig. 3, indicating sections which are shown in Fig. 5A and 5B;

Fig. 5A, in a sectional side view, shows a connection of a closed knob and a tube connector according to the invention;

Fig. 5B shows another section through the closed knob and the tube connector of Fig. 5A;

Fig. 6, in a perspective view, shows modular construction elements similar to the construction elements of Fig. 3, but where the cylindrical connector is an open knob; Fig. 7 is a bottom view of the modular construction elements of Fig. 6, indicating sections which are shown in Fig. 8A and 8B, and where the elements are connected to each other;

Fig. 8A, in a sectional side view, shows a connection of an open knob and a tube connector according to the invention;

Fig. 8B shows another section through the open knob and the tube connector of Fig. 8A;

Fig. 9, in a perspective view, shows a modular construction element, second construction element, with a tube connector according to the invention;

Fig. 10 shows a top view of the second construction element 12 and tube connector of Fig. 9;

Fig. 11A shows a section through the tube connector of Figs. 9 and 10;

Fig. 11B shows another section through the tube connector of Figs. 9 and 10;

Fig. 11C show detail of the tube connector of Fig. 11A.

Detailed description of the embodiments

Figs. 1A-D shows an example of prior art construction elements or construction elements of a modular construction system 10. Such construction elements of a modular construction system 10 are often formed in plastic in an injection moulding process. The plastic materials used in for such construction elements of a modular construction systems 10 typically has a certain strength and elasticity depending on the material thickness and form as well as other parameters. Figs. 1A and 1C show two essentially identical construction elements 2A, 2B in the shape of building blocks. Each of these construction elements 2A, 2B comprises a body part 3 with a top face 4 on which eight cylindrical connectors 100 are configured. The cylindrical connectors 100 could also be called coupling studs or coupling knobs. The cylindrical connectors 100 are formed on the construction elements 2A, 2B in a regular two dimensional lattice or grid. The cylindrical connectors 100 comprises a body 105 having an outer cylindrical surface 110.

The body part 3 of the construction elements 2A, 2B comprises sidewalls 6A, 6B, 6C, and 6D are configured, and those sidewalls A, 6B, 6C, and 6D have a lowermost edge 7 that forms a resting face for the construction elements 2A, 2B.

Construction elements 2A, 2B of the type shown in Fig. 1 are interconnected by the sidewalls 6A, 6B, 6C, and 6D on the uppermost construction element 2A being pressed outwards when the sidewalls 6A, 6B, 6C, and 6D are pressed down on the coupling studs (not shown in Fig. 1) on the lowermost construction element 2B, following which the sidewalls press against the coupling studs 100 on the lowermost construction element 2B.

Cylindrical connectors 100 formed on construction elements 2A, 2B in a regular two dimensional lattice, such as shown in Figs. 1A-D, forms the basis of a plurality of modular construction systems known in the art.

Such cylindrical connectors 100 are also known to be connectable to another type of connector, than the one shown in Fig. 1C.

For example, cylindrical connectors 100 may connect to a tube connecter 20. An example of a prior art tube connector 20 is shown in Fig.2B.

In Fig. 2B the tube connector 20 is formed on a construction element second construction element 12, which is shaped as hair of toy figurine (not shown). The second construction element 12 resembling hair may connect to another construction element, first construction element 11 shaped as a head of a toy figurine, which head has a single cylindrical connector 100, for example formed on top of the first construction element 11 resembling a head. The first construction element 11 resembling a head and the second construction element 12 resembling hair are shown in Fig. 2A, where the constructions element 11, 12 are disassembled from each other, but aligned such that the second construction element 12 with the tube connector 20 may be coupled to the first construction element 11 with the cylindrical connector 100. Thereby the head and the hair resembling first and second construction elements 11, 12 may be coupled in a press fit between the cylindrical connector 100 and the tube connector 20.

The tube connector 20 for connecting a second construction element 12 (in this case the hair resembling construction element) to a cylindrical connector 100 having a cylindrical outer surface 110 (which cylindrical connector 100 is similar to the cylindrical connectors 100 of Figs. 1A-D) of a first construction element 11, as illustrated in Fig. 2A, is configured for coupling to the cylindrical connector 100 in a press fit. For this purpose, the tube connector 20 has a tubular wall 30 surrounding a cylindrical opening 31 having a cylindrical inner surface 32, which is formed to fit over the cylindrical outer surface 110 of cylindrical connector 100. Further, the cylindrical inner surface 32 comprises four planar pressure surfaces 40’. The planar pressure surfaces 40’ are equidistantly located along the perimeter of the cylindrical inner surface 32 of the tubular wall 30. The cylindrical inner surface 32 and the planar pressure surfaces 40’ are dimensioned such that they provide the pressure fit on the cylindrical connector 100, when the tube connector 20 is pressed over the cylindrical connector 100, the tubular wall 30 of the tube connector 20 and/or the material of the cylindrical connector 100 deforming where the four planar pressure surfaces press against the outer cylindrical surface 110 of the cylindrical connector 100.

For example such connectors may be made in ABS plastic.

It has shown that the function and quality of the connections between tube connectors 20 and cylindrical connectors 100 are very sensitive to the type of material used for the making the connection, and to the dimensions such as material thickness of the construction element 12 to which they form part, etc., and that this puts demands for extreme tolerances in making of the tube connectors. Thus, in order to produce a constant quality of e.g. the clutch power of the connection between tube connectors 20 to complementary cylindrical connectors 100, for each new construction element design, a specifically dimensioned tube connector needs to be designed. Designing each time such a connection is time consuming.

It has shown that the design time and cost can be considerably reduced by a tube connector 20 according to the present invention, which is described with reference to Figs. 3-11D in the following.

A connection between a first construction element 11 and a second construction element 12 comprising a tube element 20 according to the invention is shown in Fig. 3 and 6. The set of modular construction elements 11, 12, first construction element 11 and second construction element 12 are shown in an un-connected situation.

The connection is a press fit/pressure fit, the construction elements 11, 12 having complementary coupling means in the form of a cylindrical connector 100 and a new tube connector 20 according to the invention.

Fig. 3, in perspective view, shows modular construction elements 11, 12 o, where the cylindrical connecter 100 is a closed knob, and where the construction elements 11, 12 are separated from each other, but aligned such that the tube connector may be pressed over the cylindrical connector 100 to form the configuration of construction elements 11, 12, a situation which is shown in Figs.5A-B, where the cylindrical connector 100 and the tube connector 20 may be connected in a press fit.

Fig. 4 is a bottom view of the modular construction elements 11, 12 of Fig. 3, when the construction elements are connected. Fig. 4 indicates sections A-A and B-B through the construction elements 11 shown in Fig. 5A and 5B, respectively. Fig. 5A shows section A-A to show pressure surfaces 40 of the tube connecter according to the invention, and Fig. 5B shows section B-B, showing guide surfaces 50 according to an embodiment of the invention. Fig. 5A, in a sectional side view, shows the connection of a cylindrical connection 100 in the closed knob/knob configuration, and a tube connector 20 according to the invention.

By a closed knob configuration of the cylindrical connector is meant that it has a body 105 which forms an entirely closed outer surface, such that both an outer cylindrical surface 110 and an end surface 115 of the body 105 of the cylindrical connector 100 of the first element 11 are closed surfaces. As indicated the closed knob configuration of the cylinder connection 100 may have an internal space 107 formed therein in order to allow the cylindrical outer surface 110 of the cylindrical connector 100 (or portions thereof) to deform when pressed, e.g. by pressure surfaces 40 of the tube connector 20 as described in further detail below.

Fig. 6 illustrates a connection of modular construction elements 11, 12 similar to the connection in Fig 3.

Fig. 6, in perspective view, shows modular construction elements 11, 12, where the cylindrical connecter 100 has an open knob configuration, and where the construction elements 11 , 12 are separated from each other, but aligned such that the tube connector 20 may be pressed over the cylindrical connector 100 to form the configuration of construction elements 11 , 12 shown in sections in Figs. 8A and 8B, where the cylindrical connector 100 and the tubular are connected in a press fit.

Fig. 7 is a bottom view of the modular construction elements 11, 12 of Fig. 6, when the construction elements are connected. Fig. 7 indicates sections A-A and B-B through the construction elements 11 , 12, the sections being shown in Fig. 8A and 8B, respectively. Fig. 8A shows section A-A to show pressure surfaces 40 of the tube connecter according to the invention, and Fig. 8B shows section B-B, showing guide surfaces 50 according to an embodiment of the invention.

Fig. 8A, in a sectional side view, shows the connection of a cylindrical connection 100, which has an open knob/knob configuration, and a tube connector 20 according to the invention. By an open knob configuration of the cylindrical connector is meant that it has a body 105 with a cylindrical depression 108 formed into an end surface 115 of the body 105, such that the body 105 forms a tubular wall 109, in order to allow the cylindrical outer surface 110 of the cylindrical connector 100 (or portions thereof) to deform when pressed, e.g. by pressure surfaces 40 of the tube connector 20 as described in further detail below.

In both of the embodiment described in connection with Figs. 3-5 and Figs. 6-8, respectively, the tube connection 20 is the same The two different versions differ in the cylindrical connector 100 being open or closed. However, both of these configuration are known in the art.

We now turn to Fig. 9, showing a second construction element 12 with a tube connector 20 according to an embodiment of the invention, the tube connector 20 being shown in a perspective view. The tube connecter 20 may be a tube connector 20 as described above in connection with Figs. 3-8.

As is the case above, the tube connector 20 comprises a tubular wall 30 extending from the second construction element 12. As is also the case above, the second construction element 12 is shown as a simple cylindrical structure for simplicity. It will however be appreciated that the second construction element 12 may take many other forms, for example a hair resembling element as shown in Fig. 2B.

The tube connector 20 has a depression formed as a cylindrical opening into a front surface 35 of the tube connector 20, thereby forming a tubular wall 30.

The tubular wall 30 of the tube connector 20 comprises a cylindrical outer surface 34, i.e. an outwardly facing cylindrical surface, and a cylindrical inner surface 32, i.e. an inwardly facing cylindrical surface.

A thickness of the tubular wall 30 is defined between the cylindrical inner surface 32 and the cylindrical outer surface 34. Depending on the material properties, by different thickness of the tubular wall 30, the ability to deform so as to press on a cylindrical connector 100 (not shown in Fig. 9) may be adapted. In the embodiment shown, the tube connection 20 comprises a set of pressure surfaces 40, undercuts 60 associated with the pressure surfaces 40, and guide surfaces 50.

Fig. 10 shows a top view of the second construction element 12 with the tube connector of Fig. 9.

Fig. 10 indicates a detail of a pressure surface 40 and a guide surface 50, which detail is enlarged in Fig. 11A.

Fig. 10 further indicates sections A-A and B-B through the second construction element 12, the sections shown in Fig. 11 B and 11 D, respectively. Fig. 11 B shows section A-A to show pressure surfaces 40 of the tube connecter 20 in section, and according to an embodiment of the invention, and Fig. 11D shows section B-B, showing guide surfaces 50 in section, and according to another embodiment of the invention.

Fig. 11C shows a detail of a pressure surface 40 in section, the detail indicated in Fig. 11 B.

In a preferred embodiment, the tube connector 20 comprises two and only two pressure surfaces 40 provided as protrusions from the cylindrical inner surface 32.

It has shown that - compared with the four planar pressure surfaces of the prior art - the protruding two (and only two) pressure surfaces 40 allows to quickly dimension a tube connector 20 for a second construction element 12, providing a stable press fit connection with a cylindrical connecter 100, regardless of the plastic used for moulding the second construction element 12 with the tube connector 20, and regardless of the dimensioning of the second construction element 12 as such. With the new tube connector 20 features is made possible to design the tube connector quickly and providing a robust connection with a smaller requirement for extreme tolerances in the injection moulding process. The new tube connector 20 features further makes it possible to design tube connectors 20 for many differently shaped second construction elements 12 and/or made in various materials.

The pressure surfaces 40 are configured for providing a pressure against the cylindrical outer surface 110 of the cylindrical connector 100, to induce a deformation of the cylindrical outer surface 110 of the cylindrical connector 100and/or the tube connector 20, to thereby provide the press fit connection, when the tube connector 20 is pressed over the cylindrical outer surface 110 of the cylindrical connector 100. The two and only two pressure surfaces 40 and the cylindrical inner surface 32 are configured such that no other part of the cylindrical inner surface 32 provides pressure to the cylindrical outer surface 110 of the cylindrical connector 100.

Preferably, and as shown in Figs. 9-11 , the two pressure surfaces 40 are identically shaped.

Alternatively, the two pressure surfaces 40 may be formed different from each other, dependent on the shape, material or other characteristics of the construction element and tube connector, such that qualities, such as the clutch power between the tube connector and the cylindrical connector remain within requirements. This may be advantageous when for example the second construction element 12 has an asymmetrical shape.

Preferably, and as shown in Figs. 9-11 , the two pressure surfaces 40 are formed diametrically across from each other on the cylindrical inner surface 32 of the tubular wall 30 of the tube connector 20.

Preferably, and as shown in Figs. 9-11 , the two pressure surfaces 40, each of the two pressure surfaces 40 are rectangular.

Now turning to Fig. 11 A, showing an enlarged view of the detail A, in Fig. 10, the pressure surfaces 40 has a width, W1. The width, W1 of each of the pressure surfaces 40 preferably extends over 5-60°, preferably 20-50° of the cylindrical inner surface 32 of the tube connector 20. In principle, the protruding pressure surfaces 40 may be planar. However, as shown best in Fig. 11 A, the pressure surfaces 40 form an arc parallel with the cylindrical inner surface 32 of the tub connector 20. For example, for softer plastics less pressure may be needed, and where a more arched/curved pressure surface 40 may be preferred. For harder plastic, in order to provide a larger deformation, a planar or at least more flat pressure surface 40 may be preferred.

In some (not shown) embodiments, the pressure surfaces 40 may extend from the front end surface 35 of the tubular wall 30 to a bottom surface 24 of the tube connector 20.

However, in preferred embodiments, each of the pressure surfaces 40 extends only over a partial length, L3, of the total length L1 of the cylindrical inner surface 32 of the tubular wall 30 of the tube connector 20.

The dimensioning of the pressure surfaces 40 allows to control the local deformation and friction behavior of the material in the vicinity of the pressure surfaces 40, when the cylindrical connector 100 and the tube connector 20 are coupled in the press fit connection. Preferably, the dimensioning of the pressure surfaces 40 is provided such that the local deformation is less than a certain percentage of the total diametral overlap between the pressure surfaces 40 and the cylindrical outer surface 110 of the cylindrical connector 100, depending on materials and shape of the second construction element, and the tube connector 20 length, height over the cylindrical inner surface 32 and width. Preferably, in the example shown in Fig. 3-11, the dimensioning of the pressure surfaces 40 is provided such that the local deformation is less than 33% of the total diametral overlap between the pressure surfaces 40 and the cylindrical outer surface 110 of the cylindrical connector 100.

Preferably, the pressure surfaces 40 is provided adjacent to the front end surface 35 of the tubular wall 35.

In preferred embodiments, an undercut 60 is provided between each pressure surface 40 and the bottom surface 25. The undercut allows to control the surface area of the pressure surfaces 40, together with the width, W1 , of the pressure surfaces 40, and has the function of reducing or eliminating the spring-back effect of the connection between the cylindrical connector 100 and the tube connector 20.

Turning now to Fig. 11 C, showing an enlarged view of the detail B, in Fig. 11 B, it will be appreciated that in preferred embodiments the tube connector 20 further comprises rounded intermediate surfaces between the above mentioned surfaces.

In one embodiment, a smooth rounded transition between a front surface 13 of the second construction element 12 and the outer cylindrical surface 34 of the tubular wall 30 of the tube connector 20 is provided by a rounded transition surface 37.

In one embodiment, a smooth rounded transition 36 between the outer cylindrical surface 34 and the front end surface 35 of the tubular wall 30 of the tube connector 20 is provided by a rounded transition surface 33.

In one embodiment, a smooth rounded transition between the front end surface 35 of the tubular wall 30 of the tube connector 20 and the cylindrical inner surface 32 is provided by a rounded transition surface 36. This rounded transition surface 36 ensure guidance and ease of mounting of the connection. The diameter of the rounded transition surface 36 at the entrance thereto (in an axial direction of the tube connector and towards the bottom surface 25 thereof) is larger than the diameter of the cylindrical outer surface 110 of the cylindrical connector 100. The diameter, however, narrows in an axial direction of the tube connector and towards the bottom surface 25 thereof. Therefore, at least the upper, second portion 36” serves as a catch surface, which catches the cylindrical connector 100 and guide it towards the space formed by the cylindrical opening 31 in the tube connector 20.

At the location where each of the pressure surfaces 40 transitions into the front end surface 35, preferably, the rounded transition surface 36 comprises two portions, a first portion 36’ and second portion 36”. The first portion of the rounded transition surface is adjacent to the pressure surface. A transition is provided between the first portion of the rounded transition surface and the pressure surface. This transition is preferably smooth.

The second portion 36” of the rounded transition surface 36 is further formed between the front end surface 35 and the first portion 36’ of the rounded transition surface. A transition is provided between the first portion 36’ of the rounded transition surface and the second portion 36” of the rounded transition surface. This transition is preferably smooth.

The first portion 36’ of the rounded transition surface 36 is configured for guiding the cylindrical outer surface 110 of the cylindrical connector 100 onto the pressure surface 40, during the act of connecting the tube connector 20 to the the cylindrical connector 100. The diameter between the two pressure surfaces 40 is slightly smaller than the diameter of the cylindrical outer surface 110 of the cylindrical connector 100 in order for the pressure surfaces 40 to squeeze on the cylindrical outer surface 110 of the cylindrical connector 100 and provide the pressure fit/interference fit when the two are connected .

At the axial distance from the bottom 25 of the tube connector 20 corresponding to the level of the first portion 36’ of the diameter corresponds to the diameter of outer surface 110 of the cylindrical connector 100. Therefore, when pressing the outer surface 110 of the cylindrical connector 100 towards the bottom surface 25 of the tube connector from this position, the pressure surfaces starts to squeeze on the outer surface 110 of the cylindrical connector 100. Therefore, first portion 36’of the rounded transition surface 36 is has an inclination relative to the pressure surface 40 and a shape that is configured to guide the the outer surface 110 of the cylindrical connector 100 onto the pressure surfaces 40.

The first portion 36’ of the rounded transition surface 36 thereby constitutes an inlet surface to guide the cylindrical outer surface 110 of the cylindrical connector 100 onto the pressure surface 40. Thus, the first portion is inclined relative to the pressure surface to provide a ramp for guiding the cylindrical outer surface of the cylindrical connector onto the pressure surface. Thus, the inlet surface configuration formed by the first portion prevents or at least reduces damage to the pressure surface.

Further, the first portion 36’ of the rounded transition surface 36 preferably has a transition into the pressure surface 40, and wherein this transition is smooth.

In one embodiment, a smooth rounded transition between the cylindrical inner surface 32 of the tubular wall 30 of the tube connector 20 and the bottom surface 25 of the tube connector 20 is provided by a rounded transition surface 26.

In general, the rounded surfaces also are provided for production purposes, such a de-shaping from a mould in the injection moulding process.

Also, Fig. 11C indicates lengths of the tubular wall 30 of the tube connecter 30 and the surfaces mentioned above.

In Fig. 11 C, length L1 is the total length of the cylindrical inner surface 32 from the bottom surface 25 of the tub connector 20 to the front end surface 35 of the tubular wall 30 of the tube connector 20.

In Fig. 11 C, length L2 is the length of the second portion 36” of the rounded transition surface 36 formed between the first portion 36’ of the rounded transition surface 36 and the front end surface 35 of the tubular wall 30 of the tube connector 20.

In Fig. 11 C, length L7 L2 is the length of the first portion 36’ of the rounded transition surface 36 formed between the pressure surface 40 and the second portion 36” of the rounded transition surface 36.

In Fig. 11 C, length L3, is the length of the pressure surface 40.

In Fig. 11 C, length L4 is the length of the undercut 60.

In Fig. 11 C, length L5, is the length of the cylindrical inner surface 32 portion provided under the cutouts 60. In Fig. 11 C, length L6, is the length of the rounded transition surface 37 between the front surface 13 of the second construction element 12 and the outer cylindrical surface 34 of the tubular wall 30 of the tube connector 20.

The lengths mentioned above, are defined in the axial direction of the tube connector 20.

Now turning to Fig. 11 A, the tube connector 20, may further comprises at least one guide surface 50. The purpose of the guide surface is to guide the cylindrical outer wall 110 of the cylindrical connector 100 into contact with the pressure surfaces 40 of the tube connector 40, and to secure the planar location in relation to the two dimensional lattice or grid defined the modular construction system.

In preferred embodiments, and as shown in Fig. 11A, the tube connector 20 comprises two guide surfaces 50. Preferably, these two guide surfaces 50 are located diametrically across from each other on the cylindrical inner surface 32 of the tubular wall 30 of the tube connector 20.

In preferred embodiments, and as also shown in Fig. 11 A, the guide surfaces 50 are planar.

In further preferred embodiments, and as shown in Fig. 11 D, the guide surfaces 50 extends from the front end surface 35 of the tube connector 20 to a bottom surface 25 of the tube connector 20.

As will be appreciated from e.g. Fig. 11 D, the protrusion, on which each of the pressure surface 40 are formed on, further comprises a side surface 45 is formed on both sides of the pressure surface 40 of each protrusion, in a direction perpendicular to an axial direction of the tube connector 20.

Each of the side surfaces 45 transitions into the cylindrical inner surface 32 of the tube connector 20. Thus, the side surfaces 45, the undercut 60 and the first portion 36’ of the of the rounded transition surface 36 secures that the pressure surface 40 is elevated above the cylindrical inner surface 32 of the tube connector 20.

Thereby, it is secured that the two pressure surfaces 40 form discrete areas that may press on the cylindrical outer surface 110 of the cylindrical connector 100. Thereby, the pressure surfaces 40 may provide the above mentioned deformation of at least a portion of the cylindrical outer surface 110 of the cylindrical connector 100.

When correctly sized and shaped, the pressure surfaces 40 provides a local deformation that may be controlled by the dimensioning of the pressure surfaces 40.

Referring again to Fig. 11A, the guide surfaces 50 each has width, W2. In preferred embodiments, the width, W2, of each guide surface 50 extends over 15-30° of the cylindrical inner surface 32 of the tube connector 20.

Preferably, the two guide surfaces 50 are formed at 90° from the two pressure surfaces 40 on the cylindrical inner surface 32 of the tubular wall 30 of the tube connector 20.

The tube connector 20 on the second construction element may also be referred to as a female tube connector. The tube connector 20 may allow a press fit connection with an element with a cylindrical circumferential surface (cylindrical outer surface 110), provided a desired, predictable, and reliable functionality, measured in drawing force, with low sensitivity towards geometrical misalignment.

The geometrical principles applied in the interface are generic and, therefore, not limited by geometrical sizes or material selection. Dimensioning for target functionality is more easily obtained than for the prior art four planar pressure surfaces by faster dimensioning of pressure surfaces 40 ensuring a local deformation relative to the stiffness of the tube connector 20 depending on material properties and material thickness. Spring-back effect is understood as an angled reaction force pushing the interface apart. This phenomenon is very sensitive to geometrical misalignment and has a significant impact on experienced functionality and the maximum overlap of the pressure surfaces.

The desired functionality (measured in drawing force) is created by the press fit connection with overlap on the two protruding pressure surfaces 40 (local deformation control), and through friction between the interfacing surfaces protruding pressure surfaces 40 and the cylindrical outer surface 110 of the cylindrical connector 100, the and the spring-back effect is eliminated with the implemented undercut 50. The guide surfaces 50 ensure desired positioning and grid compatibility without impacting functionality.

It is to be noted that the figures and the above description have shown the example embodiments in a simple and schematic manner. Many of the specific mechanical details have not been shown since the person skilled in the art should be familiar with these details and they would just unnecessarily complicate this description. For example, the specific materials used and the specific injection moulding procedure have not been described in detail since it is maintained that the person skilled in the art would be able to find suitable materials and suitable processes to manufacture the container according to the current invention.

List of parts

2A prior art modular construction element

2B prior art modular construction element

3 body part of prior art modular construction element

4 top face of prior art modular construction element

6A side of prior art modular construction element

6B side of prior art modular construction element

6C side of prior art modular construction element

6D side of prior art modular construction element

7 lower edge of prior art modular construction element

10 modular construction system

11 first constructions element of the modular construction system

12 second construction element of the modular construction system

13 front surface of the second construction element

20 tube connector

25 bottom surface of the tube connector

26 rounded transition surface between the bottom surface of the tube connector and the cylindrical inner surface of the tubular wall of the tube connector

30 tubular wall of the tube connector

31 cylindrical opening in the tube connector

32 cylindrical inner surface of the tubular wall of the tube connector

33 rounded transition surface between the front end surface and the outer cylindrical surface of the tubular wall of the tube connector

34 outer cylindrical surface of the tubular wall of the tube connector

35 front end surface of the tubular wall of the tube connector

36 rounded transition surface between the cylindrical inner surface and the front end surface of the tubular wall of the tube connector

37 rounded transition surface between the front surface of the second construction element and the outer cylindrical surface of the tubular wall of the tube connector

40 pressure surface

45 side surface to the pressure surface

50 guide surface 100 cylindrical connector of first element

105 body of cylindrical connector of first element

107 internal space of body of cylindrical connector of first element

108 cylindrical depression formed into an end surface 115 of the body 109 tubular wall of cylindrical connector 100

110 cylindrical outer surface of cylindrical connector of first element

115 end surface of body of cylindrical connector of first element

L1

W1 width of pressure surface W2 width of guide surface

Claims

1. A tube connector (20) for a modular toy construction system (10), wherein said modular toy construction system (10) comprises a first construction element (11), and a second construction element (12), wherein the first construction element (11) comprises a cylindrical connector (100) having a cylindrical outer surface (110), wherein the second construction element (12) is provided with the tube connector (20), wherein the tube connector is configured for coupling to the cylindrical connector (100) in a press fit, wherein the tube connector (20) comprises a tubular wall (30) surrounding a cylindrical opening (31) and having a cylindrical inner surface (32) formed to fit over the cylindrical outer surface (110) of the cylindrical connector (100), characterized in that the cylindrical inner surface (32) is provided with two and only two pressure surfaces (40) protruding from the inner cylindrical surface (32), which pressure surfaces (40) are configured for providing a pressure against the cylindrical outer surface (110) of the cylindrical connector (100), and where no other part of the cylindrical inner surface (32) provides pressure to the cylindrical outer surface (110) of the cylindrical connector (100), when the tube connector (20) and the cylindrical connector (100) have been connected to each other.

2. A tube connector (20) according to claim 1 , wherein each of the two pressure surfaces (40) are configured such that in at least an axial direction of the tube connector (20), the pressure surface (40) is formed substantially parallel with the cylindrical inner surface (32).

3 A tube connector (20) according to claim 1 or 2, wherein each of the two pressure surfaces (40) are configured such that in at least an axial direction of the tube connector (20), the pressure surface (40) is formed substantially parallel with the cylindrical outer surface (110) of the cylindrical connector (100), when the tube connector (20) and the cylindrical connector (100) have been connected to each other. 4. A tube connector (20) according to any one of the claims 1-3, wherein a rounded transition surface (36) is provided between the pressure surface (40) and a front end surface (35) of the tube connector (20) for each of the two pressure surfaces (40).

5. A tube connector (20) according to claim 4, wherein at least a first portion (36’) of the rounded transition surface (36) is configured for guiding the cylindrical outer surface (110) of the cylindrical connector (100) onto the pressure surface (40), during the act of connecting the tube connector (20) to the the cylindrical connector (100).

6. A tube connector (20) according to claim 4, wherein the first portion (36’) of the rounded transition surface (36) has a transition into the pressure surface (40), and wherein this transition is smooth.

7. A tube connector (20) according to any one of the claims 1-6, wherein, for each of the two pressure surfaces (40), an undercut (60) is provided between the pressure surface (40) and the bottom surface (25) of the tube connector (20).

8. A tube connector (20) according to claim 7, wherein, for each of the two pressure surfaces (40), the surface defining the undercut (60) is adjacent to the respective pressure surface (40).

9. A tube connector (20) according to claim 7 or 8, wherein a transition is provided between the pressure surface (40) and the undercut (60), and where the transition is smooth.

10. A tube connector (20) according to any one of the claims 7-9, wherein the undercut (60) transitions into the cylindrical inner surface (32) of the tube connector (20), and wherein the transition is smooth.

11. A tube connector (20) according to any one of the claims 1-10, wherein for each of the two pressure surfaces (40), a side surface (45) is formed on both sides of the pressure surface (40) in a direction perpendicular to an axial direction of the tube connector (20).

12. A tube connector (20) according to claim 11 , wherein each of the side surfaces (45) transitions into the cylindrical inner surface (32) of the tube connector (20).

13. A tube connector (20) according to any one of the claims 1-12, wherein, for each of the two pressure surfaces (40), when the tube connector (20) and the cylindrical connector (100) have been connected to each other, a clearance surrounds the protrusion on which the pressure surface (40) is formed.

14. A tube connector (20) according to any one of the claims 1-13, wherein, for each of the two pressure surfaces (40), when tube connector (20) and the cylindrical connector (100) have been connected to each other, the pressure provided by the protruding pressure surface (40) provides a deformation of at least a portion of the cylindrical connector (100).

15. A tube connector (20) according to claim 14, wherein the deformation of at least a portion of the cylindrical connector (100) is a local deformation of the cylindrical outer surface (110) of the cylindrical connector (100).

16. A tube connector (20) according to any one of the claims 1-17, wherein the two pressure surfaces (40) are located diametrically across from each other on the cylindrical inner surface (32) of the tubular wall (30) of the tube connector (20).

17. A tube connector (20) according to any one of the claims 1-16, wherein each of the two pressure surfaces are rectangular.

18. A tube connector (20) according to any one of the claims 1-17, wherein a width (W1) of each of the pressure surfaces extends over 5-60° of the cylindrical inner surface (32) of the tube connector (20).

19. A tube connector (20) according to any one of the claims 1-18, wherein the cylindrical inner surface (32) is further provided with a guide surface (50) configured to provide contact with the cylindrical outer surface (110) of the cylindrical connector (100) without providing a deformation of the cylindrical outer surface (110) of the cylindrical connector (100) or the tubular wall (30).

20. A tube connector (20) according to claim 19, wherein the guide surface (50) is planar.

21. A tube connector (20) according to claim 18 or 19, wherein the guide surface (50) extends from a front end surface (35) of the tube connector (20) to a bottom surface (25) of the tube connector (20).

22. A tube connector (20) according to any one of the claims 18-21 , wherein a width (W2) of guide surface (50) extends over 10-45° of the cylindrical inner surface (32) of the tube connector (20).

23. A tube connector (20) according to any one of the claims 18-21 , wherein the tube connector (20) comprises two guide surfaces (50).

24. A tube connector (20) according to claim 23, wherein the two guide surfaces (50) are located diametrically across from each other on the cylindrical inner surface (32) of the tubular wall (30) of the tube connector (20).

25. A tube connector (20) according to claim 23 or 24, wherein the two guide surfaces (50) are formed at 90° from the two pressure surfaces (40) on the cylindrical inner surface (32) of the tubular wall (30) of the tube connector (20).

26. A modular construction system (10) comprising

- a first construction element (11), and

- a second construction element (12), wherein the first construction element (11) comprises a cylindrical connector

(100) having a cylindrical outer surface (110), and wherein the second construction element (12) is provided with the tube connector (20) according to any one of the claims 1-25.