Method of manufacturing a tube snap fastening arrangement

Abstract

The invention relates to a method (100) for manufacturing a fastening arrangement for fastening a collar to a tube. The method comprises the steps of providing a hollow tube (10), arranging said tube for receiving at least one forming punch (30) in the axial direction of the tube, punching the tube with a forming punch at an inner radial part of an edge portion (16) of the tube in the axial direction of the tube, locally reducing the tube thickness, so that the material being punched is plastically relocated in the axial direction, locally forming a snap portion (11) in the form of a flange (12) in the radial direction towards the hollow inside of the tube, providing a collar (20) configured to be arranged on the tube, wherein the collar comprises at least one receiving portion (21) arranged to receive said snap portion, and arranging the collar to the tube such that the snap portion engages with said receiving portion.

Claims

1. A method for fastening a tube to a collar in a furniture arrangement, the method comprising steps of: a) providing a hollow tube formed of a material, the tube having a material thickness surrounding the circumference of the tube forming an inner surface towards a hollow of the tube and an outer surface facing radially outwards, b) arranging said tube for receiving at least one forming punch in an axial direction of the tube, c) punching said tube with the at least one forming punch at a plurality of locations along an inner radial part of an edge portion of the tube in the axial direction of the tube, locally reducing the tube thickness at the plurality of locations along the inner surface of the tube, so that at least of the plurality of locations the material being punched is plastically relocated from the edge portion to a location along the inner surface of the tube, locally forming a snap portion in the form of a flange in the radial direction towards the hollow inside of the tube, wherein a distance along the inner surface of the tube between one snap portion and a second snap portion is different from another distance along the inner surface between the one snap portion and a third snap portion, d) providing a collar configured to be arranged on said tube, wherein the collar comprises at least one receiving portion configured to receive said at least one snap portion (11a-h), and e) arranging the collar to the tube such that the snap portion engages with said receiving portion.

2. The method according to claim 1, wherein the flange assumes a shape corresponding to the shape of the forming punch.

3. The method according to claim 1, wherein the flange thickness depends on the amount of material being relocated by the punch.

4. The method according to claim 1, wherein the forming punch comprises a hook forming portion, so that upon punching, the flange assumes a hook shaped edge.

5. The method according to claim 1, wherein the arranging step b) comprises arranging the tube in a holder and arranging a punching die at the location of where the flange is to be located so that the forming punch is pushed towards said punching die and the flange is formed against said punching die.

6. The method according to claim 5, wherein the punching die has a surface onto which the flange is pushed so that the underside of the flange assumes the shape of the punching die.

7. The method according to claim 6, wherein the tube has a material thickness of 2 to 15 mm.

8. The method according to claim 1, further comprising a subsequent flange forming step to adjust the dimensions and/or shape of said flange.

9. The method according to claim 1, further comprising a trimming step for trimming at least one of the tube and the flange.

10. The method according to claim 1, wherein the tube is a metal tube.

11. The method according to claim 1, wherein the collar is made of a plastic material.

12. A method for fastening a tube to a collar in a furniture arrangement, the method comprising steps of: a) providing a hollow tube formed of a material, the tube having a material thickness surrounding the circumference of the tube forming an inner surface towards a hollow of the tube and an outer surface facing radially outwards, b) arranging said tube for receiving at least one forming punch in an axial direction of the tube, c) punching said tube with the at least one forming punch at an inner radial part of an edge portion of the tube in the axial direction of the tube, locally reducing the tube thickness at a portion of the inner surface of the tube, so that the material being punched is plastically relocated from the edge portion to a location along the inner surface of the tube, locally forming at least one snap portion in the form of a flange in the radial direction towards the hollow inside of the tube, d) providing a collar configured to be arranged on said tube, wherein the collar comprises at least one receiving portion configured to receive said at least one snap portion (11a-h), and e) arranging the collar to the tube such that the snap portion engages with said receiving portion, wherein the punching step c) is preceded by or including a warming step, which includes warming the forming punch and/or the tube in order to soften the material and facilitate the relocation of the material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will in the following be described in more detail with reference to the enclosed drawings, wherein:

(2) FIG. 1 is a perspective view of a fastening arrangement according to an embodiment of the invention,

(3) FIG. 2 is a perspective view of a fastening arrangement according to an embodiment of the invention,

(4) FIG. 3a is a side view of a schematic figure of the manufacturing method according to an embodiment of the invention,

(5) FIG. 3b is a cross sectional side view of a schematic figure of the manufacturing method according to an embodiment of the invention,

(6) FIG. 4 is a perspective view of a forming punch according to an embodiment of the invention,

(7) FIG. 5 is a top view of a fastening arrangement according to an embodiment of the invention,

(8) FIG. 6 shows a product according to an embodiment of the invention,

(9) FIG. 7 is a cross sectional view of a schematic figure of a collar according to an embodiment of the invention, and

(10) FIG. 8 is a flow chart of a method according to an embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

(11) The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown.

(12) Referring to FIG. 1, there is shown a fastening arrangement 100 according to the invention. The fastening arrangement is arranged to fix a tube 10 and a collar 20 to each other. The tube 10 comprises a flange 12 being arranged to be received in a receiving portion 21 in the collar 20. The tube 10 has an outer surface 2 and an inner surface 1. The inner surface 1 is provided with a flange 12 which is part of a snap portion 11 of the fastening arrangement 100. The snap portion 11 is configured to be arranged in a receiving portion 21 of the collar 20. It may be called snap portion 11 since the flange may be arranged such that it snaps in place in the receiving portion 21 and may thus be fixed. The collar 20 may thus be arranged on the tube 10 so that the snap portion 11 and the receiving portion 21 are engaged. As seen, the snap portion 11 is arranged on the inner surface 1 of the tube 10 at an edge portion 16 of the tube 10. The inner side 1 is the side facing the inner hollow of the tube 10. The outer surface 2 is the opposite side of the inner surface 1.

(13) Referring to FIG. 2, the tube 10 with a snap portion 11 is shown in more detail. The tube 10 in FIG. 1 has a thickness t and a width w. The snap portion 11 comprises a flange 12. The snap portion 11 according to an embodiment is manufactured by relocating material from one location of the tube 10 to form the flange 12. The relocation of the material is done by pushing the material along the inner surface 1. The material is not removed from the tube 10, to be reinstated therein. The material is relocated as part of the tube 10, and plastically moves along the tube 10 to its final location and forming the flange 12. Due to the relocation of material, and thus formation of the flange 12, a groove 15 is formed where the material originally was located.

(14) In FIGS. 3a and 3b, it is schematically shown the method of forming the flange 12. The tube 10 is provided. The tube 10 has a thickness t and a width w, and an inner surface 1 and an outer surface 2. The tube 10 is prepared for receiving a punch from a forming punch 30. The forming punch 30 hits the tube at an edge portion 16 towards the inner surface 1. The forming punch 30 punches the tube 10 so that material from the tube 10 is pushed in the punching direction Y towards a second location forming a flange 12. The punching direction may be vertical, but the tube may also be arranged so that the punching is done in another direction. The flange may assume the shape of the forming punch 30. As shown schematically in FIGS. 3a and 3b, the forming punch 30 may have a shape that forms a flange 12 with a triangular cross section. The forming punch 30 may also be curved and or include a ridge of some sort in order to transfer this shape onto the flange 12. The forming punch 12 is in this schematic figure rectangular and leaves a rectangular flange. However, the forming punch 30 may be any other suitable shape in order to produce a suitable shaped flange 12.

(15) Referring to FIGS. 4 and 5, there are shown a forming punch 30 with a patterned punch surface 31 in FIG. 4. The patterned punch surface 31 of the forming punch 30 may transfer to the flange upper surface 13. In FIG. 5 there is a top view of a tube with a formed flange 12 and where the flange has a patterned flange upper surface 13. The pattern may be any suitable pattern such as ridges, rifles, or grooves which may add extra grip or other functions to the fastening arrangement 100. The flange upper surface 13 may in other embodiments be formed without a pattern.

(16) FIG. 6 shows a tube arrangement 100 according to the invention. Here is shown a tube 10 in the form of a hollow tube. The collar 20 is a collar to be arranged on an edge 16 of the tube 10. The collar 20 has a top portion 23 and a side portion 24. The side portion may be inserted in the tube until an underneath surface 25 of the top portion 23 rests on the edge 16 of the tube 10. When being arranged in place, the fastening arrangement 100 is formed. The snap portion 11a-h snaps into the corresponding receiving portions 21a-h by means of the flanges 12. The tube 10 in the figure is a rectangular hollow tube. It may be emphasized that this product does not limit the field of use for the fastening arrangement according to the invention. The fastening arrangement may be equally useful with fastening other elements than a tube and a collar.

(17) FIG. 7 is a cross sectional view of a schematic figure of a collar 20 according to an embodiment of the invention. The collar 20 has a top portion 23 and a side portion 24. The top portion has an underneath surface 25. In this schematic figure the edges are sharp. However, it is possible that the edges are rounded or chamfered. The side portion 24 may also be tapered. The top portion 23 may have a thickness of Tt and a width Wt. The side portion may have a thickness Ti and a length Li.

(18) FIG. 8 illustrates a flow chart of a method 200 according to an embodiment of the present invention. The method 200 comprises the steps of providing S1 a hollow tube 10, arranging S2 the tube for receiving a forming punch in the axial direction at the edge portion 16 of the tube 10, punching S3 the tube 10 with a forming punch 30 at an inner radial part of the edge portion 16, to form a snap portion 11 in the form of a flange 12, providing S4 a collar 20 configured to be arranged on the tube and comprising a receiving portion 21a-h configured to receive the snap portion, and arranging S5 the collar 20 on the tube 10 such that the snap portion 11 engages with the receiving portion 21a-h.

(19) In the drawings and specification, there have been disclosed preferred embodiments and examples of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation, the scope of the invention being set forth in the following claims.

REFERENCE NUMERALS

(20) 100 fastening arrangement 10 tube 11 snap portion 12 flange 13 flange upper surface 15 groove 16 edge portion 1 inner surface 2 outer surface 20 collar 21 receiving portion 23 top portion 24 inner portion 25 underneath surface 30 forming punch 31 punch surface 40 holder 41 punching die