Furniture parts comprising a male part and a female part of a joint

Abstract

The disclosure relates to a first furniture part adapted to be assembled with a second furniture part. The first furniture part comprises recess and the second furniture part comprises a pin. The recess and the pin has a width which varies along the longitudinal direction (L), thereby forming insertion portions of the recess and core portions of the pin, and respective locking portions. The locking portions are provided with grooves and protrusions. The disclosure further relates to a second furniture part comprising a male part of the joint and to a method of forming a furniture part with a female part of a joint.

Claims

1. Furniture part comprising a male part of a joint, wherein the male part of the joint comprises a pin extending from a base of the furniture part along a height direction (H) towards a free end of the pin, the pin having a cross-section with a pin length (PL) extending along a longitudinal direction (L) and a width (W) which is perpendicular to the longitudinal direction (L), which width (W) varies along the longitudinal direction (L), wherein the pin has, as seen along the longitudinal direction (L), a first portion forming a locking portion and having a first width (W.sub.21), a second portion connected to the first portion and forming a core portion and having a second width (W.sub.22) being smaller than the first width (W.sub.21), a third portion forming a locking portion and having a third width (W.sub.21), wherein opposing, longitudinally extending, side wall portions of the first portion are each provided with a first protrusion and a second protrusion extending alongside each other and both extending in the longitudinal direction (L) along the first portion and extending outwardly in the direction of the width (W) from a first portion core width (W.sub.20) to said first width (W.sub.21), wherein the first protrusion is located at a first height (H.sub.23a) of the pin and the second protrusion is located at a second height (H.sub.23b) of the pin, which second height (H.sub.23b) is larger than the first height (H.sub.23a), wherein opposing, longitudinally extending, side wall portions of the third portion are each provided with a first protrusion and a second protrusion extending alongside each other and both extending in the longitudinal direction (L) along the third portion and extending outwardly in the direction of the width (W) from a third portion core width (W.sub.20) to said third width (W.sub.21), wherein the first protrusion is located at a first height (H.sub.23a) of the pin and the second protrusion is located at a second height (H.sub.23b) of the pin, which second height (H.sub.23b) is larger than the first height (H.sub.23a), and wherein, at the transition between the first and second portion and at a portion of the third portion facing away from the second portion, respective protrusion comprises an initial portion formed by a gradual increase in height of upper and lower wall portions of the cross-section of the protrusion as seen counter to the longitudinal direction (L).

2. Furniture part according to claim 1, wherein a greatest width (W.sub.21) of the first or third portion of the pin is at least 50% of a minimum width (W.sub.2) along the base of the furniture part.

3. Furniture part according to claim 1, wherein each protrusion, across the longitudinal direction (L), has an essentially V-shaped cross-section, comprising an upper major wall portion being inclined in a direction outwardly and downwardly and a lower major wall portion being inclined in a direction outwardly and upwardly and a protrusion top portion connecting said upper and lower wall portions.

4. Furniture part according to claim 1, wherein the male part of the joint is integrally formed in the furniture part.

5. Furniture part according to claim 1, wherein the initial portion of the third portion is formed by the end of the third portion facing away from the second portion having a convex curvature.

6. Furniture part according to claim 1, wherein the initial portion constitutes between 10% and 33% of the active length of respective protrusion, wherein the active length is considered to be the length the second furniture part slides along the first furniture part as the parts are locked together.

7. Furniture part according to claim 1, wherein the first protrusion of the first portion has the same cross-sectional shape as and is aligned with the first protrusion of the third portion, and wherein the second protrusion of the first portion has the same cross-sectional shape as and is aligned with the second protrusion of the third portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will by way of example be described in more detail with reference to the appended schematic drawings, which shows a presently preferred embodiment of the invention.

(2) FIG. 1a shows a first furniture part with a female part of a joint and a second furniture part with a male part of the joint.

(3) FIG. 1b shows the parts of the joint being aligned relative to each other for insertion or removal.

(4) FIG. 1c corresponds to FIG. 1b and shows an alternative embodiment.

(5) FIG. 2 shows the male part of the joint being inserted into the female part of the joint and indicates the direction towards the locked position.

(6) FIG. 3a shows the furniture parts in the locked position.

(7) FIG. 3b shows the parts of the joint in the locked position.

(8) FIG. 4 corresponds to FIG. 1a and shows the female part of the joint in a cross-section.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(9) As shown in the figures, a first furniture part 1 adapted to be assembled with a second furniture part 2. The first furniture part 1 comprises a female part of the joint and the second furniture part 2 comprises a male part of the joint, wherein the female part of the joint is adapted to receive the male part of the joint.

(10) The female part of the joint comprises an elongate recess 10 extending along a longitudinal direction L. The recess 10 has a width W.sub.11, W.sub.12 which varies along the longitudinal direction L and a depth D. Along the longitudinal direction L, the recess 10 has three insertion portions 11a-c. The insertion portions 11a-c are equidistantly arranged. The insertions portions 11a-c has a width W.sub.11. The recess 10 further comprises three locking portions 12a-c. The locking portions 12a-c are equidistantly arranged. The locking portions 12a-c has a width W.sub.12, which is smaller than the width W.sub.11 of the insertion portions 11a-c. The insertion portions 11a-c are basically formed as circular cylindrical holes to a depth D into the first furniture part 1. The width W.sub.11 of the insertion portions 11a-c is basically the diameter of the insertion portions 11a-c. The walls of the insertion portions 11a-c are smooth walls. Two (12a, 12c) of the locking portions 12a-c are formed as two, along the longitudinal direction L straight walled narrower portions located between the insertion portions 11a-c. It may be noted that straight relates to the fact that they are straight along the longitudinal direction. Along the depth direction D they are provided with grooves. The end locking portion 12b is also formed with a straight walled portion along the longitudinal direction L and terminates in a circular end with a diameter equal to the width W.sub.12.

(11) Opposing longitudinal side wall portions 14a-c of the locking portions 12a-c are each provided with a first groove 13a extending in the longitudinal direction L and being located at a first depth D.sub.13a of the recess 10 and a second groove 13b extending in the longitudinal direction L and being located below the first groove 13a at a second depth D.sub.13b of the recess 10.

(12) The male part of the joint comprises a pin 20 extending from a base 2 along a height direction H towards a free end of the pin 20. The pin 20 has an elongated cross-section extending along the longitudinal direction L and having a width W which varies along the longitudinal direction L. Along the longitudinal direction L, the pin 20 has three locking portions 21a-c. The locking portions 21a-c are equidistantly arranged. The locking portions 21a-c has a width W.sub.21. The pin 20 further comprises two insertions or core portions 22a-b. The core portions 22a-b have a width W.sub.22, which is smaller than the width W.sub.21 of the locking portions 21a-c.

(13) Opposing side wall portions 24a-c of the locking portions 21a-c are each provided with a first protrusion 23a extending along the longitudinal direction L and extending outwardly from a core width W.sub.20 to the outer width W.sub.21 of the locking portions 21a-c and being located at a first height H.sub.23a of the pin 20, and with a second protrusion 23b extending along the longitudinal direction L and extending outwardly from a core width W.sub.20 to the outer width W.sub.21 of the locking portions 21a-c and being located above the first protrusion at a second height H.sub.23b of the pin 20.

(14) It may be noted that if the recess 10 is designed with only two insertion portions and two locking portions, it is preferred that the two portions are designed as the end portions in the shown embodiment and that the centre insertion portion and the centre locking portion are removed.

(15) It may be noted that the nomenclature in the description of the preferred embodiment of the recess may be translated to the nomenclature of the description of the recess under the heading summary of the invention according to the following. The end insertion portion 11a is also denoted the first insertion portion. The other end insertion portion 11b in the longitudinal direction L is also denoted the third portion. The end locking portion 12a is also denoted the second portion. The other end locking portion 12b is also denoted the fourth portion.

(16) Thus, in the preferred embodiment of the recess there is a set of portions from first to fourth portions and the recess further comprises an additional insertion portion and an additional, associated locking portion located between the set comprising the first and second portions and the set comprising the third and fourth portions. It may be noted that there may be any desired number of such additional sets of an insertion portion and an associated locking portion between the associated first and second portions and the associated third and fourth portions.

(17) It may be noted that if the pin 20 is designed with only two locking portions and one insertion or core portion, it is preferred that the two locking portions are designed as the two end portions in the shown embodiment. The core portion will preferably be designed as any one of the core portions in the shown embodiment.

(18) It may be noted that the nomenclature in the description of the preferred embodiment of the pin may be translated to the nomenclature of the description of the pin under the heading summary of the invention according to the following. The end locking portion 21a is also denoted the first portion. The core portion 22a is also denoted second portion. The other end locking portion 21b is also denoted third portion.

(19) Thus, in the preferred embodiment of the recess there is a set of portions from first to third portions and the pin further comprises an additional core portion and an additional locking portion located between the second portion forming the core portion and the third portion forming the end locking portion. It may be noted that there may be any desired number of such additional sets of a core portion and an associated locking portion between the second portion and the third portion.

(20) It is also contemplated to design the joint with a pin having one locking portion followed by an elongated core portion (as seen in a direction counter the longitudinal direction). The recess will in such a case preferably have a locking portion, followed by a core portion and by a guiding portion (as seen in a direction counter the longitudinal direction). The core portion of the pin is in such a case preferably of such length along the longitudinal direction that it may engage with the side walls of the guiding portion of the recess.

(21) The first furniture part 1 is joined together with the second furniture part 2 in accordance with the following steps.

(22) First the second furniture part 2 is oriented and positioned relative the first furniture part 1 such that the locking portions 21a-c of the pin 20 are aligned with the core portions 21a-c of the recess 10. This is shown in FIG. 1a.

(23) Thereafter the second furniture part 2 is moved (in a translational movement) relative to the first furniture part 1 in a direction along the height H of the pin 20 to insert the pin 20 of the second furniture part 2 into the recess 10 of the first furniture part 1. The insertions portions 11a-c of the recess 10 have such shape and dimensions that they can accommodate the locking portions 21a-c of the pin. The core portions 22a-b of the pin 20 have such shape and dimensions that they can be inserted in the locking portions 12a, 12c of the recess 10. This movement is indicated with the arrow M1 in FIG. 1a. The position after this movement M1 is shown in FIG. 1b and FIG. 2.

(24) Thereafter the second furniture part 2 is moved relative to the first furniture part 1 along the longitudinal direction L such that the protrusions 23a-b of the pin 20 enters into the grooves 13a-b of the recess 10. This movement is indicated with the arrow M2 in FIG. 2. The position after this movement M2 is shown in FIG. 3a and FIG. 3b.

(25) When the furniture parts 1, 2 has been joint together in the position shown in FIG. 3a the engagement between the grooves 13a-b and the protrusions 23a-b prevents the pin 20 from being pulled outward in the height/depth direction. The grooves 13a-b and protrusions 23a-b are designed such that there will be a frictional engagement between the surfaces of the grooves 13a-b and protrusions 23a-b. Basically they are preferably designed such that there is a slight interference fit between the grooves 13a-b and protrusions 23a-b. Preferably the heights H.sub.23a and H.sub.23b of the positions of the protrusions 23a-b and the depths D.sub.13a and D.sub.13b of the grooves 13a-b are chosen such that there will be a slight interference fit between the surface 1a in which the recess 10 is formed and the surface 2a from which the pin 20 extends. It is preferred that the surfaces 1a and 2a are major surfaces of the furniture parts 1, 2 (at least in the vicinity of the recess and pin). It is e.g. preferred that the surface 1a of the first furniture part 1 has such an extension in the width direction on both sides of the recess that the surface 2a of the second furniture part 2 may slide along the surface 1a during the movement M2. However it may be noted that the surfaces 1a, 2a need not be major surfaces of the furniture parts 1, 2, but may instead be at a plane different from the major surfaces of the furniture parts 1, 2.

(26) As shown in FIG. 1b and FIG. 1c, the greatest width W.sub.11 of the insertion portions 11a-c is about 75% of the width W.sub.1 of the furniture part 1 along the recess 10. Since the side wall parts of the insertion portions 11a-c will not carry any load they may from a load bearing perspective basically be as thin as the manufacturing process allows. However, the thickness of the walls still needs to be sufficient such that there is sufficient load bearing capacity of the wall in those parts of the wall extending along the locking portions and being located outside the bottoms of the grooves. For strong wood based materials, such as natural wood, glued timber pieces, wood laminates, or laminates of wood-like materials, such as bamboo, it is contemplated that the insertion portions 11a-c may have a width W.sub.11 being up to about 90% of the width W.sub.1 of the furniture part 1 along the recess 10. For comparably weaker wood based materials, such as wood based composite materials, such as fibreboards, chipboards, or the like, it is contemplated that the insertion portions 11a-c may have a width being up to about 50% of the width W.sub.1 of the furniture part 1 along the recess 10.

(27) Similarly, a greatest width W.sub.21 of the locking portions 21a-c of the pin is at least 50% of a minimum width W.sub.2 along the base of the furniture part 2. This is considered efficient use of the material thickness to provide a strong pin 20. In practice a greatest width W.sub.21 of the locking portions 21a-c of the pin is less than 100% of a minimum width W.sub.2 along the base of the furniture part 2.

(28) As shown in FIG. 1a, each groove 13a-b has across the longitudinal direction L an essentially V-shaped cross-section. In the cross-section the grooves 13a-b has an upper major wall portion 13a-b being inclined in a direction outwardly and downwardly and a lower major wall portion 13a-b being inclined in a direction outwardly and upwardly and a groove bottom portion 13a-b connecting said upper and lower wall portions 13a-b and 13a-b.

(29) The grooves 13a-b are also provided with a small longitudinally extending protrusion 13a-b. The protrusion 13a-b is formed in the upper major wall portion 13a-b. This protrusion 13a-b aids in forming a frictional engagement between the first and second furniture part 1, 2 without making it too difficult to slide the two parts 1, 2 in the relative movement M2. The protrusions 13a-b are so small that they are fairly easily deformed as the customer moves the second part 2 in the relative movement M2. The protrusions may alternatively be at the male part.

(30) As is shown in FIG. 4, at the transitions between the insertion portion 11a and the locking portion 12a, between the insertion portion 11c and the locking portion 12c, and between the insertion portion 11b and the locking portion 12b, respective groove 13a-b of the locking portions 12a-c comprises an inlet portion 12a-c. As viewed from above, the side wall portion of the locking portion is at this inlet portion 12a-c inclined inwardly from the insertion portion 11a-c towards the minimum width W.sub.12 of the locking portions 12a-c. Thereby the result will be that the upper and lower wall portions 13a-b, 13a-b will increase in height (in the width direction) when following the longitudinal direction L from the insertion portions 11a-c to respective locking portion 12a-c. This way the grooves 13a-b will initially present a shallow V-shape which makes it easy to find the right position for the protrusions 23a-b of the pin 20 without any jamming effect occurring. The inlet portions 12a-c constitute between 10% and 33% of the active length of respective groove. The active length is in this embodiment considered to be the distance travelled in sliding movement M2. When the pin 20 is inserted into the recess 10 there is no locking engagement between protrusions 23a-b and grooves 13a-b. As the parts 1, 2 are slid relative to each other in the movement M2, there will be a locking engagement with the length equal to the length of the movement M2. This is true since there is no distance between the starting point of the grooves and the insertion portion of the recess, or between the starting point of the protrusions and the core portion of the pin. If the design is such that there is a gap or distance between the insertion portion and the grooves of the recess or a gap between the core portion and the protrusions of the pin, the greatest of those distances should be deducted from the length of the movement M2 to determine the active length of the grooves and protrusions.

(31) As shown in FIG. 1a, each protrusion 23a-b has across the longitudinal direction L an essentially V-shaped cross-section. In the cross-section the protrusions 23a-b has an upper major wall portion 23a-b being inclined in a direction outwardly and downwardly and a lower major wall portion 23a-b being inclined in a direction outwardly and upwardly and a protrusion top portion 23a-b connecting said upper and lower wall portions 23a-b and 23a-b.

(32) As shown in the figures, at the transition between the core portion 22a and the locking portion 21a, between the core portion 22b and the locking portion 21c, and at a portion of the locking portion 21b facing away from the other locking portions 21a, 21c, respective protrusion 23a-b comprises an initial portion 21a-c. As viewed from above, the side walls of the pin 20 are at this initial portion 21a-c inclined outwardly from the core portions 22a-b towards the locking portions 22a, 22c. As viewed from above, the end portion of the locking portion 22b is circular thereby also presenting an inclined surface. Thereby the result will be that the upper and lower wall portions 23a-b, 23a-b will increase in height (in the width direction) when following the longitudinal direction L from the core portion 22a towards the locking portion 21a, and from the core portion 22b towards the locking portion 21c. The initial portion 21a, 21c constitutes between 10% and 33% of the active length of respective protrusion. The initial portion 21b may constitute a greater fraction since it will enter into an end portion of the recess 10 and thereby carry load once fully inserted into the end of the recess.

(33) It is contemplated that there are numerous modifications of the embodiments described herein, which are still within the scope of the invention as defined by the appended claims.

(34) As shown in FIG. 1c, the recess 10 may be provided with a wedge shape 15a-c overlaying the shape of the grooves 13a-b of the locking portions 12a-c. The wedge shape 15a-c may be a formed by a wedge shape of the side walls 14a-c such that the distance between the side walls 14a-c. Such a wedge shape may e.g. entail that the width of the recess 10, decreases when following the longitudinal direction L. The wedge shape 10 may alternatively be formed by a wedge shape of the cross-section of the grooves 13a-b of the locking portions. The angle of upper and lower walls forming the cross-section of the grooves may e.g. be changed such that the space available for the protrusions 23a-b of the pin 20 will decrease when following the longitudinal direction L. Alternatively, the wedge shape may be a combination of the two alternatives mentioned. It may also be noted that the wedge shape may alternatively be formed on the pin 20 instead.

(35) Other modifications may entail that the pin may for instance be formed of a separately formed member which is attached to the second furniture part. The pin may in such a case be formed of another material, such a plastic material.

(36) One specific site of application for the furniture joint is e.g. cross braces for stabilising the legs of a chair. Basically the joint is useful for applications where a comparably thin bar is adapted to be attached to another furniture part. In such a case the comparably thin bar is advantageously provided with the pin and the other furniture part is advantageously provided with the recess.