Field of invention

The invention relates to a fastening device for mounting a furniture leg or support element to a furniture article, such as a table or chair.

Background

Among different techniques developed for connecting a furniture leg to a furniture, one of the most common technique is to use fasteners and brackets. Despite the fact that fasteners and brackets are used widespread for simpler furniture designs, a more sophisticated furniture with decorative elements, such as a table leg that is not perpendicular to the plane defined by the table itself or to the surface onto which the leg is placed, requires a more complex fastening device. However, such a complexity increases the number of parts of the fastening device, resulting in increased variable cost and manual labour after purchase.

For example, U.S. Pat. No. 3,516,633 discloses a furniture leg mount, comprising a T- nut having a portion on one side of a furniture support member and projecting at a predetermined angle toward the opposite surface of the member, enabling the leg to be placed at an inclination angle. One of the disadvantages of this design is that the inclination of the furniture leg is fixed by the disclosed mounting. Another disadvantage is that further drilling in the support member is required, which makes the mounting rather complicated and cumbersome.

While some attempts have been made to permit rotational adjustability of furniture legs with an advanced flexibility and stability, these attempts have not solved the problem entirely to this date. In certain instances, the fastening device restricts rotational adjustability, as it offers only one or a few pre-defined inclination angle(s). In other instances, the method involves a trial and error practise of assembly and disassembly until a stable positioning of the legs is secured.

State of the art shows that different fastening device designed for securing a leg element to a furniture article with an inclination angle are either very costly or complex to such a degree that it is time consuming to assemble and disassemble the device. This does not only add to the ultimate cost of the piece of furniture, but adds to the sales resistance on the part of the retailers. Thus, there is a demand for an adjustable fastening device, which in a simple and durable way allows furniture legs of different inclination angles to be mounted on to furniture articles by both amateur and professional craftspeople without the need of any complex tools but standard tools, such as a screwdriver.

Summary

Considering the prior art described above, it is an purpose of the present invention to provide a simple and durable fastening device, enabling the mounting of a furniture leg having a predefined inclination angle, i.e. the inclination angle that the leg element forms relative to the furniture article and/or the ground.

One embodiment of the present disclosure relates to an adjustable fastening device for securing a leg element to a furniture article, i.e. an adjustable leg fastening device, in particular an adjustable furniture leg fastening device, aka a (furniture) leg connector. The leg element has a top surface and an inclination angle defined by an angle between the top surface and a longitudinal extension of the leg element. The adjustable fastening device comprises a mounting bracket and at least one bearing element. The mounting bracket further comprises a bottom surface, which during use faces the top surface of the leg element. The mounting bracket may further be provided with one or more openings I holes, e.g. in the form of at least one slot, and preferably at least a first engagement surface, which advantageously is provided in accordance with said slot(s). The bearing element(s) may further comprise a second engagement surface configured to rotatably engage with the first engagement surface(s). The bearing element(s) is configured to be attached to the leg element through the slot, e.g. by means of one or more screws going through the bearing element, the corresponding slot and into the leg element. Advantageously the adjustable fastening device is configured such that when the bearing element(s) is attached to the leg element through the corresponding slot, the first and second engagement surfaces automatically rotatably adjust such that the top surface of the leg element becomes parallel with the bottom surface of the mounting bracket.

The presently discloses adjustable fastening device is preferably configured such that initially a leg element, with a predefined inclination angle, is assembled to the mounting bracket by means of the bearing element(s), such that the bearing element(s) sits inside the mounting bracket. Assembly of the bearing element(s) to the leg element may be performed by means of at least one fastener unit such as screw. Then, the bearing element rotatably can adjust until the top surface of the leg element is parallel to the bottom outer surface of the mounting bracket. This implies that the presently disclosed fastening device can self-adjust in relation to the inclination angle of the furniture leg. One of the advantages of the presently disclosed fastening device, is thereby that by the rotatable engagement between the bearing element(s) and the mounting bracket, the fastener unit(s) can be mounted parallel to the extension of the leg.

A further advantage of the present invention, in which the fastening device is self- adjusting, is that the furniture legs are not required to be adjusted manually for a desired angle since the leg elements are manufactured with a pre-defined inclination angle. Thus, with the presently disclosed fastening device, it is possible to provide an adjustable leg mounting while ensuring a homogeneously distributed load and stability during use.

The present invention meets the gap of a need for a simple and durable fastening device that allows furniture legs of different inclination angles to be mounted on to furniture articles by both amateur and professional craftspeople without the need of any complex tools.

Particularly, the invention may be obtained in the form of a kit of parts comprising a fastening device and corresponding fastening units, such as screws adapted for the bearing elements, and optionally instructions for use.

Description of the drawings

The invention will in the following be described in greater detail with reference to the accompanying drawings:

Figs. 1 A-B show one embodiment of the presently disclosed fastening device, a leg element, and screws, wherein a central lines of the bearing elements in fig. 1A indicate the fixing direction of the fastening device to the leg element.

Fig. 2 is an exploded view of embodiment of the fastening device, wherein the mounting bracket and two bearing elements are shown. Fig. 3 is a schematic view of the fastening device, showing the bearing elements located in the grooves in the mounting bracket.

Fig. 4 is a schematic view showing the bottom surface of the fastening device.

Fig. 5 is a cross-sectional schematic view of the fastening device seen from the side, showing the rotated bearing elements sitting in the grooves in the mounting bracket.

Detailed description

The presently disclosed fastening device is intended for, but not exclusive to, securing a leg element to a furniture article such as a table, a chair, a stool and other related furniture articles, in particular furniture articles with leg elements.

The present invention will now be described more fully hereinafter with reference to the accompanying exemplary embodiments of the invention shown in the drawings when applicable. However, it is to be noted that the invention may be embodied in various forms. The hereby provided embodiments are to guide a thorough and complete disclosure. Hence, embodiments set forth herein should not be interpreted as limiting but be construed as a tool for delivering the scope of the invention to those who are skilled in the art. Same reference numbers refers to the same element throughout the document.

Fig. 1A shows an exploded isometric view showing a leg element 3 and one embodiment of the presently disclosed fastening device wherein the shown central line through the bearing elements indicate the fixing direction of the screws when attaching the fastening device to the leg element. The fastening device comprises a mounting bracket 1 configured to be assembled to a furniture article (not shown). The fastening device further comprises two bearing elements 2, designed such that the bearing elements 2 can be integrated inside the mounting bracket 1 and engage with the inner surfaces of the mounting bracket 1 , when the fastening device is in use. The dotted central lines in Fig. 1A indicate the assembly direction of the fastening device to the furniture leg 3.

In one embodiment of the present disclosure, the fastening device is attached to the furniture leg 3 by means of a fastening unit, e.g. in form of two screws 22, that pass through first bearing elements 2 and after the mounting bracket 1 and finally screws 22 connect to the leg element 3 through the prednlled holes 20 located on the top surface 4 of the leg element 3. In the same embodiment, fastening device is in a position where the bearing elements 2 rotate, such that the direction of the screws 22 are parallel to the leg extension 5.

A front view of a leg element 5 and one embodiment of the presently disclosed fastening device is provided in Fig 1B. The leg element 3 has a top surface 4 and a predefined inclination angle. As seen from fig. 1 B there are several ways to define the predefined inclination angle of a leg element. The inclination angle is the angle between the top surface 4 and one side 5 of the leg element. The inclination angle a is the angle between the top surface 4 and the opposite side 5’ of the leg element 3. The inclination angle 0 is the angle between the top surface and the longitudinal extension of the screws inside the leg element 3, which is defined by the longitudinal extension of the pre-drilled holes 20. As seen in fig. 1 B the bearing elements 2 can rotate within the xy plane, which is parallel to the front view plane given in Fig 1B, to adjust to the inclination angle 0; therefore, the axis of rotation of the bearing elements 2 is parallel to the z-axis. Even if the predrilled holes 20 were provided as non-parallel extensions into the leg element, or in the case of no predrilled holes, the configuration of the bearing elements 2 and the mounting bracket 1 with their engagement surfaces will still make sure that the bearing elements rotatably adjust in the mounting bracket such that the bottom surface of the mounting bracket become plane with the top surface 4 of the leg element 3, i.e. even if it is attached with two screws that does not extend parallel into the leg element.

Fig. 2 is an exploded view of an embodiment of the fastening device, wherein the mounting bracket 1 and two bearing elements 2a, 2b are shown further in detail. In the figures the presently disclosed fastening device is exemplified with two bearing elements, but in principle only one bearing element is needed for the rotatable adjustment, but increased stability is typically achieved with more than one bearing element. Fig. 2 also shows the inner surface of the mounting bracket that faces the furniture article during use. The mounting bracket 1 has a certain height to make room for a void space in the inner surface for housing the first engagement surface(s) and the bearing element(s). In another embodiment the presently disclosed fastening device comprises more than two bearing elements, preferably located along said slot, or in separate slots. The multiple bearing elements may be placed at a distance there between such that the bearing elements are parallel to each other at the same planar height in order to improve the handling of the device during assembly.

As exemplified in Fig. 2, one embodiment of the mounting bracket 1 comprises a bottom surface 6 which during use faces the top surface of the leg element 4, at least one slot 7, and engagement surfaces 8a-d in accordance with said slot 7. Hereby, an engagement with the bearing element 2 is ensured, furthermore a fastening unit to assemble the fastening device to the furniture leg 3 is provided through said slot 7. The bearing element 2 further comprises at least a second engagement surface 9 configured to rotatably engage with the first engagement surface 8. In one embodiment of the presently disclosed fastening device, the first engagement surface 8 and the second engagement surface 9 are designed such that they define a rotation axis of the bearing element in a plane, which is parallel with the bottom surface 6 of the mounting bracket. As exemplified in fig. 2 the two bearing elements 2a, 2b define to parallel rotation axes in a plane parallel with a plane defined by the bottom surface 6. Hence, in one embodiment the interface between corresponding first engagement surface 8 and second engagement surface 9 defines one or more rotation axes of the bearing element 2 in a plane, which is parallel with a plane defined by the bottom surface of the mounting bracket.

In a further embodiment of the presently disclosed fastening device the first engagement surface(s) is at least one groove 8 formed in the mounting bracket 1, each groove substantially formed like a cradle. Said groove 8 and a corresponding slot 7 may be located in the bottom surface of the mounting bracket 1. Preferably, the slot 7 coincides with the first engagement surface 8, such that said slot divides each first engagement surface into two separate grooves, i.e. transversely, cf. example in Fig. 2 where four grooves 8a, 8b, 8c, 8d form two pairs of engagement surfaces in the mounting bracket 1.

In an embodiment, the first engagement surface(s) 8 of the mounting bracket 1 has a similar curvature as said second engagement surface(s) 9 of the bearing element such that a conformal contact there between is enabled. Preferably, the first engagement surface(s) 8 of the mounting bracket is concave and the second engagement surface(s) 9 of the bearing element is convex. Alternatively, the first engagement surface(s) of the mounting bracket is convex and the second engagement surface(s) of the bearing element(s) is concave, In order to allow a rotational degree of freedom of the bearing element 2, the preferred geometry of the engagement surfaces is circular. An advantage of the presently disclosed fastening device is that it allows for rotational degree of freedom providing a reduced friction between engaging surfaces. Thus, the handling of the device is eased due to reduced forces as well as longer lifetime of the fastening device is provided.

In one embodiment, bearing element(s) 2a, 2b comprise at least one hole 24a, 24b; preferably, the hole has a central axis perpendicular to the longitudinal-rotational axis of the corresponding bearing element, such that.at least one fastening element, such as a screw, can pass through said hole of the bearing element and said slot of the mounting bracket and secure the leg element to the mounting bracket 1. The hole in a bearing element is preferably notched for full integration of a corresponding screw. In an embodiment, the at least first engagement surface is a half-cylindrical groove with spherical ends, wherein the groove height corresponds to the radius of the cylinder, as exemplified in Fig. 2. Furthermore at least one bearing element 2 may be formed as a half cylinder with spherical ends defining the second engagement surface(s) 9. Thus, in an embodiment, the at least first engagement surface can be a semi-cylindrical groove with at least one quarter-spherical end and wherein said at least one bearing element can be formed as a semi-cylinder with quarter-spherical ends defining the second engagement surface.

Fig. 2 also shows four grooves 8a, 8b, 8c, 8d and a slot 7 located at the inner surface of the mounting bracket 1 facing the furniture element upon fixation. The slot 7 is located along the middle of the bottom surface 6 of the mounting bracket 1, such that the slot 7 divides the two engagement surfaces of the mounting into two pairs of grooves 8a, 8b, 8c, 8d. Each pair of grooves engages with one bearing element 2 when the fastening device is in use, i.e. such that one bearing element 2a engages with two grooves 8a, 8b and the other bearing element 2b engages with the other two grooves 8c, 8d. The axis of rotation of the bearing elements 2a, 2b is located on the top surface 10 of the half-cylindrical bearing elements 2a, 2b. Hence, the top surface 10 of the each bearing element 2a, 2b becomes perpendicular to the longitudinal extension of the corresponding screw extending through the bearing element and into the leg element 5 when the fastening device is in use. As also seen in fig. 2 the top surface of the bearing elements 2a, 2b is provided with a notch such that the top surface of a matching screw can become plane with the top surface of the bearing element to make the fastening device as thin as possible.

Fig. 3 shows one embodiment of a schematic view of the fastening device, wherein the bearing elements 2a, 2b are in contact with the grooves 8 of the mounting bracket 1. The bearing elements 2a, 2b are attached to the leg element 3 through the slot 7. During the assembly, the first 8 and second 9 engagement surfaces automatically rotatably adjust such that the top surface of the leg element 4 becomes parallel with the bottom surface 6 of the mounting bracket. The bottom surface 6 of the mounting bracket 1 is illustrated in Fig. 4. The mounting bracket 1 may be securely attached to the furniture article by means of at least one fastening unit, such as screw(s). Fig 4. further shows six holes 26a, 26b, 26c, 26d, 26e, 26f (with notches) in the mounting bracket 1 for enabling fastening of the mounting bracket 1 to the furniture article by means of screws. As also exemplified in the figures the fastening device is preferably configured such that the mounting bracket is attached to the furniture article after the leg element has been attached to the mounting bracket.

Fig. 5 shows a cross-sectional schematic view of one embodiment of the presently disclosed fastening device seen from the side, when bearing elements 2a, 2b are sitting on the first engagement surface in form of grooves 8 and rotatably adjusted to an inclination angle.

The presently disclosed fastening device is preferably made of a rigid material, such as steel, preferably stainless steel, such as SAE 304 stainless steel, but it could also be made in zinc, aluminum, brass, and even plastic.

In the preferred embodiment, the bearing element(s) is configured rotate to self-adjust to a predefined inclination angle such that the rotary self-adjustment is limited when the top surface of the leg element becomes parallel with the bottom surface of the mounting bracket. In that regard the most stable attachment is provided when the top surface of the leg element is flat and to match the bottom surface of the mounting bracket (see Fig. 1 B) as such contact between flat interfaces will provide for a homogeneous load distribution. An advantage of the presently disclosed adjustable fastening device is that bearing element(s) is configured to rotate to self-adjust such that said fastening device can be used and re-used for a range of inclination angles, such as between 0 and 60, more preferably between 0 and 45 degrees, most preferably between 0 and 25 degrees such that it can be used for many different types of leg elements. The maximum inclination angle is at least partly determined by the height I thickness of the mounting bracket, which typically is between 5 and 25 mm, more preferably between 10 and 15 mm. The mounting bracket exemplified in the drawings has a thickness of approx. 13 mm which in this case provides a maximum inclination angle of 25 degrees.

Items

1. An adjustable fastening device for securing a leg element to a furniture article, the leg element having a top surface and an inclination angle defined by an angle between the top surface and a longitudinal extension of the leg element, the adjustable fastening device comprising:

• a mounting bracket comprising

■ a bottom surface which during use faces the top surface of the leg element,

■ at least one slot,

■ at least a first engagement surface in accordance with said slot(s), and

• at least one bearing element comprising at least a second engagement surface configured to rotatably engage with the first engagement surface(s), the bearing element(s) configured to be attached to the leg element through the slot, wherein the adjustable fastening device is configured such that when the bearing element(s) is attached to the leg element through the corresponding slot, the first and second engagement surfaces automatically rotatably adjust such that the top surface of the leg element becomes parallel with the bottom surface of the mounting bracket.

2. The fastening device according to item 1, wherein the interface between corresponding first and second engagement surface defines a single rotation axis of the bearing element in a plane, which is parallel with the bottom surface of the mounting bracket.

3. The fastening device according to any of the preceding items, wherein the first engagement surface(s) is at least one groove formed in the mounting bracket.

4. The fastening device according to any of the preceding items, wherein the first engagement surface(s) of the mounting bracket is concave and the second engagement surface(s) of the bearing element is convex.

5. The fastening device according to any of the preceding items, wherein the first engagement surface(s) of the mounting bracket has a similar curvature as the second engagement surface(s) of the bearing element such that a conformal contact there between is enabled.

6. The fastening device according to any of the preceding items, wherein the at least first engagement surface is a half-cylindrical groove with spherical ends.

7. The fastening device according to any of the preceding items, wherein said at least one bearing element is formed as a half cylinder with spherical ends defining the second engagement surface.

8. The fastening device according to any of the preceding items, wherein the at least one slot coincides with the first engagement surface such that said slot divides each first engagement surface into two separate grooves.

9. The fastening device according to any of the preceding items, wherein the bearing element further comprises at least one hole with a central axis perpendicular to the rotational axis of the bearing element, and optionally at least one fastening element, such as a screw, configured to pass through said hole of the bearing element and said slot of the mounting bracket and secure the leg element to the mounting bracket.

10. The fastening device according to any of the preceding items, wherein said bearing element(s) is configured rotate to self-adjust to a predefined inclination angle such that the rotary self-adjustment is limited when top surface of the leg element becomes parallel with the bottom surface of the mounting bracket.

11 . The fastening device according to any of the preceding items, configured to be used a range of inclination angles, such as between 0 and 60, more preferably between 0 and 45 degrees, most preferably between 0 and 25 degrees, such that it can used for many different types of leg elements.

12. The fastening device according to any of the preceding items, comprising a plurality, such as two, of said bearing elements located along said slot.

13. The fastening device according to any of the preceding items, wherein multiple bearing elements are placed at a distance such that said bearing elements are parallel to each other at the same planar height.

14. The fastening device according to any of the preceding items, configured such that the mounting bracket attaches to the furniture article in a rigid fashion by means of at least one fastening element, such as screw(s).

15. The fastening device according to any of the preceding items, configured such that the mounting bracket is attached to the furniture article after the leg element has been attached to the mounting bracket.

16. A kit of parts comprising a fastening device according to any of the preceding items, and fastening elements for the fastening of the mounting bracket and/or bearing element to the surface of the furniture and instructions for use.

17. A piece of furniture comprising at least one leg element and at least one adjustable fastening device according to any of the preceding items.