FIELD OF THE INVENTION

The invention relates to a device having a support for placing the device on a surface. The invention further relates to such a device in the form of a luminaire, such as a table lamp, a desk lamp, or a floor-standing lamp, and to a method of manufacturing such a device by means of fused deposition modelling.

BACKGROUND OF THE INVENTION

A device that should be placed on a surface typically has a support with a base that is connected (or arranged to be connected) to an end of a stand. Such a device may be a luminaire, for example a table lamp, a desk lamp, or a floor-standing lamp.

To avoid wobbling, it is important that the device can be placed in a stable position on the surface. This can be achieved if the base has a flat lower surface. However, the slightest deviation from a flat lower surface may already cause the device to be unstable.

When the stand and the base of the support are separate parts that should be coupled together upon assembly of the device, besides ensuring a stable placement of the device, the base and the stand should fit together properly to provide a connection that is robust and free of rattle. Depending on the manufacturing process and its associated production tolerances, it may be quite difficult to fulfill these requirements. For example, a fit between the stand and the base that is too tight may result in a deformation of the base that causes it to no longer have a sufficiently flat lower surface.

Manufacturing processes that are relatively prone to such difficulties are 3D printing processes. A 3D printing process is a process wherein a material is joined or solidified under computer control to create a three-dimensional object of almost any shape or geometry. Such three-dimensional objects are typically produced using data from a three- dimensional model, and usually by successively adding material layer by layer.

An example of a 3D printing process is fused deposition modeling (FDM), which is also called fused filament fabrication (FFF) or filament 3D printing (FDP). FDM is one of the most commonly used forms of 3D printing. In an FDM process, a 3D printer creates an object in a layer-by-layer manner by extruding a printable material (typically a filament of a thermoplastic material) along tool paths that are generated from a digital representation of the object. The printable material is heated just beyond solidification and extruded through a nozzle of a print head of the 3D printer. The extruded printable material fuses to previously deposited material and solidifies upon a reduction in temperature. In a typical 3D printer, the printable material is deposited as a sequence of planar layers onto a substrate that defines a build plane. The position of the print head relative to the substrate is then incremented along a print axis (perpendicular to the build plane), and the process is repeated until the object is complete.

FDM printers are relatively fast and low-cost, and they can be used for printing complicated three-dimensional objects. Such printers are used in printing various shapes using various 3D printable materials.

FDM is currently being developed in the production of various types of devices, including those that should be placed on a surface, such as luminaires in the form of table lamps, desk lamps, and floor-standing lamps.

As indicated above, for these kind of devices it is important that they have a support that allows the device to be placed in a stable position, and when the support has a stand and a base that need to be connected, these parts should fit together properly. At the same time, 3D printing processes such as FDM may have production tolerances that make it quite difficult to meet all these requirements. A further complicating factor is that 3D printed parts may exhibit a certain degree of shrinkage, which may be dependent on the geometry of the 3D printed part.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a device having a support for placing the device on a surface, wherein the support has a stand and a base that are arranged to fit together properly to provide a connection between them that is robust and free of rattle, while at the same time the device can be placed on the surface in a stable position, and wherein the device can be manufactured by means of a process that typically has relatively large production tolerances, such as 3D printing, in particular FDM.

In a first aspect, the invention provides a device having a support for placing the device on a surface. The support comprises a stand with a first end opposite to a second end along an axis of the support. The support further comprises a base arranged to be connected to the first end of the stand. The base has three connectors. Each connector has a connector part that is coupled to the (remainder of the) base via a resilient element.

The connector part has a connector end for connecting the base to the stand by means of a snap-fit connection.

Each resilient element is arranged such that, upon application of a force on the respective connector end in a first direction towards the axis of the support, the connector end is displaced over a first distance in the first direction and over a second distance in a second direction perpendicular to the first direction and parallel to the axis of the support, to form a leg extending from the base and away from the stand.

In a cross section perpendicular to the axis of the support, the legs are arranged on the vertices of a triangle.

By connecting the base the stand, the device according to the first aspect is provided with a three-legged support which serves to maintain the stability of the device when placed on a surface.

Each resilient element may have a first part with a first elastic modulus and a second part with a second elastic modulus, wherein the first elastic modulus is higher than the second elastic modulus, and wherein the first part and the second part are both connected to the respective connector part. In this configuration, the first part of the resilient element may be rigid.

In an example of the above configuration, the base is shaped as a truncated cone having a top side and an opposite bottom side, separated from each other by a side wall. The top side, the bottom side, and the side wall together bound a hollow interior. The top side of the base has a circular surface, and the bottom side of the base has a circular rim.

Each connector is provided in the side wall of the base, interrupting the circular rim of the bottom side of the base.

The connector part has a slanted side surface between the connector end and the circular surface of the top side of the base.

Each resilient element that couples a respective connector part to the base has two components that are arranged next to each other and on opposite sides of the respective connector part. The two components have substantially the same shape, being that of a hollow oblique circular cone, an apex of the cone connecting to the top side of the base.

For each resilient element, the first part is adjacent to the top side of the base, and the second part is adjacent to the bottom side of the base. The above example has a design that allows the base to be easily manufactured by means of fused deposition modelling.

In the device according to the first aspect, the legs may have substantially the same length, and/or the legs may be arranged on the vertices of an equilateral triangle. These configurations ensure optimal stability when the device is placed on a surface.

In the device according to the first aspect, the stand may have a hollow interior, and the base may then have an entry for allowing, for example, a cable to pass into the hollow interior of the stand.

An example of the device according to first aspect is a luminaire. The luminaire may comprise a lampshade, a light source, and a cable for providing power to the light source. The lampshade and the light source may be arranged at the second end of the stand (i.e., opposite to the first end, where the base is connected to the stand). The cable may be partly arranged in the hollow interior of the stand and partly extending from the support via the entry of the base.

In a second aspect, the invention provides a method for manufacturing a device according to the first aspect, by means of fused deposition modelling. The method comprises layer-wise depositing a 3D printable material to create the stand and the base of the support.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Fig. 1 shows a device having a support for placing the device on a surface.

Fig. 2 shows an exploded view of a support comprising a stand and a base.

Fig. 3 shows a cross section of a base in a plane perpendicular to the axis of a support.

Figs 4(a) and 4(b) illustrate the principle based on which a connector enables a base to be connected to the stand by means of a snap-fit connection.

Figs 5(a) to 5(d) show an example of a base that can be connected to a stand to form a support for a device.

Fig. 6 shows a cross section of a model of the base illustrated in Figures 5(a) to 5(d). Figs 7(a) and 7(b) show photographs of a support having a stand that is connected to a base by means of three snap-fit connections, wherein each of the stand and the base has been manufactured by means of fused deposition modelling.

The drawings are schematic and not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Figure 1 shows a device 100 having a support 200 for placing the device 100 on a surface 900. The device of Figure 1 is a luminaire in the form of a table lamp. Alternatively, the device may be a luminaire in the form of a desk lamp or a floor-standing lamp, or any other device that should be placed on a surface.

Figure 2 shows an exploded view of the support 200, wherein the support 200 comprises a stand 300 and a base 400.

The stand 300 has a first end 310 opposite to a second end 320 in a direction along an axis 210 of the support 200.

The base 400 is arranged to be connected to the first end 310 of the stand 300.

Figure 3 shows a cross section of the base 400 in a plane perpendicular to the axis 210 of the support 200. The base 400 has three connectors 410. Each connector 410 has a connector part 412 that is coupled to the remainder of the base 400 via a resilient element 413. Each connector 410 extends in a direction from the center of the base 400 towards the edge of the base 400. The directions wherein the three connectors 410 extend are separated from each other by about 120 degrees.

Figures 4(a) and 4(b) illustrate the principle based on which each connector 410 enables the base 400 to be connected to the stand 300 by means of a snap-fit connection.

Prior to application of a force F (see Figure 4(a)), the connector end 410 is located at a point P _± . After application of the force F in a direction towards the axis 210 (see Figure 4(b)), the connector end 410 has moved from point P _± to point P ₂ . In other words, the connector end 410 has moved over a first distance D _± in a first direction towards the axis 210, and also over a second distance D ₂ in a second direction parallel to the axis 210.

Upon application of a force F in a direction towards axis 210, connector end 410 essentially rotates or pivots around point R. Here, this particular movement is caused by connector end 410 being coupled to a rigid first part 414, and to an elastically deformable second part 415.

The first part 414 and the second part 415 together constitute a resilient element. For the purpose of achieving the desired movement of the connector end 410 (as indicated in Figure 4(b)), the first part 414 does not have to be rigid, as long as it has a higher elastic modulus than the second part 415 (or, in other words, as long as the first part 414 is stiffer than the second part 415). When the first part 414 and the second part 415 have approximately the same elastic modulus, the second distance D ₂ will be (substantially) zero. When the second part 415 is stiffer than the first part 414, the second distance D ₂ will be in a direction opposite to what is indicated in Figure 4(b).

Figures 5(a) to 5(d) show an example of a base 500 that can be connected to a stand to form a support for a device, wherein the connection of the base to the stand works based on the principle as illustrated in Figures 4(a) and 4(b).

Figure 5(a) shows the base 500 in perspective view. The base 500 is shaped as a right circular conical frustum (also referred to as a truncated cone) having an axis that coincides with the axis 210 of the support.

The base 500 has a top side 510 and an opposite bottom side 520, separated from each other by a side wall 530. When the support is assembled, the top side 510 faces towards the stand and the bottom side 520 faces away from the stand.

The base 500 has a hollow interior bounded by the top side 510, the bottom side 520, and the side wall 530.

The top side 510 of the base 500 has a circular surface, and the bottom side 520 of the base 500 has a circular rim. Three connectors 540 are provided in the side wall 530 of the base 500, each connector 540 interrupting the circular rim of the bottom side 520 of the base 500. The latter is most evident in the view of Figure 5(b), which shows the base 500 as seen in a direction along the axis 210 towards the bottom side 520.

Each connector 540 has a connector end 541 that is provided on a connector part 542, which in turn has a slanted side surface 543 between the connector end 541 and the circular surface of the top side 510 of the base 500. This is most evident in the view of Figure 5(c), which shows a cross section of the base 500 along the axis A as indicated in Figure 5(b), and it can also be seen in the side view of Figure 5(d).

At a side opposite to the connector end 541, the connector part 542 is coupled to the remainder of the base 500 via a resilient element 544. The configuration of the connector 540, with the connector end 541, the connector part 542 and the resilient element 544 can best be seen in the bottom view of Figure 5(b).

The connector end 540 has a recess or notch, to allow the base 500 to be connected to the stand by means of a snap-fit connection, wherein the recess or notch of the connector end 541 interlocks with a protrusion of the stand. Essentially, each connector 540 of the base 500 forms a cantilever snap-fit joint with the stand.

The resilient element 544 that couples the connector part 542 to the remainder of the base 500 has two components that are arranged next to each other and on opposite sides of the connector part 542. The two components have substantially the same shape, being that of a hollow oblique circular cone, wherein an apex of the cone connects to the top side 510 of the base 500.

For each of these two components, a first part that is adjacent to the top side 510 of the base 500 has an elastic modulus that is higher than that of a second part that is adjacent to the bottom side 520 of the base 500. In fact, the elastic modulus gradually increases in a direction from the bottom side 520 of the base 500 towards the top side 510 of the base 500 (or, in other words, in a direction towards the apex of the cone).

When the support is assembled by connecting the base 500 to the stand, a force is applied on each connector end 541 in a first direction towards the axis 210 of the support. The design of the resilient element 544 then ensures that the connector end 541 is displaced over a first distance in the first direction, but also over a second distance in a second direction perpendicular to the first direction and parallel to the axis 210 of the support. This results in the formation of three legs (one for each connector), each extending from the base 500 and away from the stand.

When viewed in a cross section perpendicular to the axis 210 of the support, these three legs are arranged on the vertices of a triangle. In other words, by connecting the base 500 to the stand, the device is provided with a three-legged support which serves to maintain the stability of the device when placed on a surface. For optimal stability, the legs have substantially the same length, and they are arranged on the vertices of an equilateral triangle.

The aforementioned design allows the base 500 to be easily manufactured by means of fused deposition modelling. The design is such that the base 500 can be printed in a single continuous line, which is commonly referred to as spiralized printing or vase mode printing. The base 500 can be represented by a model having a wall that is one layer thick, and that essentially has no separable layers.

Figure 6 shows a cross section 600 of the aforementioned model in a plane perpendicular to the axis 210, corresponding to the bottom side 520 of the base 500. The cross section 600 may also be referred to as a slice of the model. From Figure 6 it is clear that this slice may be printed as a single continuous line, and the same holds for subsequent parallel slices of the same model.

Figures 7(a) and 7(b) show photographs of a support 700 having a stand 710 that is connected to a base 720 by means of three snap-fit connections 730.

The stand 710 and the base 720 have both been manufactured by means of fused deposition modelling, using polycarbonate as printing material.

The stand 710 is shaped as a truncated cone with a height of 180 mm. The side of the stand 710 that is facing towards the base 720 has a diameter of 124 mm, and the side that is facing away from the base 720 has a diameter of 67 mm.

The stand 710 has a hollow interior, and the base 720 has an entry for allowing a cable 750 to pass into the hollow interior of the stand 710.

The base 720 has a design that is similar to that of the base 500 of Figures 5(a) to 5(d). The height of the base 720 is 32 mm. The top side of the base 720 has a circular surface with a diameter of 93 mm, and the bottom side has a circular rim with a diameter of 103 mm. The connector ends of the three connectors of the base 720 are at a distance of 60 mm from a center axis of the base 720. In other words, the connectors interrupt the circular rim of the bottom side of the base 720, and the connector ends protrude from the circular rim over a distance of about 9 mm.

The bottom side of the stand 710 has an annular edge that protrudes inwardly from the circular rim. Each connector end of the base 720 has a recess or notch, located at 27 mm from the top side of the base 720. The recesses are arranged to fit with the annular edge of the stand 710 to form three snap-fit connections 730.

Using a force gauge, the spring constants at two distinct locations on the connectors have been measured. At the location of the recess in the connector end (i.e., at 29 mm from the top side of the base 720), the measured spring constant is in a range of 25.0 to 28.0 N/mm. At a location of 16 mm from the top side of the base 720, the measured spring constant is in a range of 32.1 to 34.8 N/mm. In other words, over a distance of 11 mm, in a direction from the recess towards the top side of the base 720, the spring constant increases with about 7 N/mm, which in this case amounts to an increase by a factor of about 1.3.

Such a gradient in spring constant (or in stiffness of the construction of the connector) ensures that, upon assembly of the stand 710 and the base 720, the support 700 is provided with a leg 740 at the location of each snap-fit connection 730. These leg 740 have a length L, and they extend from the base 720 and away from the stand 710. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined.