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Patent Searching and Data


Title:
FURNITURE FASTENER INTERCONNECTION
Document Type and Number:
WIPO Patent Application WO/2011/103625
Kind Code:
A1
Abstract:
A method of improving the holding force of fasteners (11, 41, 71) into timber and timber substitutes such as particle board and medium density fibreboard (5). A flowable harden able substance such as polypropylene or PVC is formed as a protrusion (7, 27) into a timber or timber substitute. A threaded fastener (11, 41, 71) is then secured into the protrusion and preferably through the protrusions and into the timber or timber substitutes. Such fasteners can be used to secure joinery mongery such as hinges (63) or latches to the timber or timber substitute. Such an arrangement has a significantly increased withdrawal force.

Inventors:
WELSH GREGORY BRENT (AU)
Application Number:
PCT/AU2011/000195
Publication Date:
September 01, 2011
Filing Date:
February 24, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SEBEL FURNITURE LTD (AU)
WELSH GREGORY BRENT (AU)
International Classes:
F16B12/14; B25B27/14; B29C45/14; B29C65/00; F16B13/14
Foreign References:
US3492381A1970-01-27
US4755130A1988-07-05
DE4417340A11995-11-23
US2663662A1953-12-22
Attorney, Agent or Firm:
FRASER OLD & SOHN (275 Alfred StreetNorth Sydney, NSW 2060, AU)
Download PDF:
Claims:
CLAIMS

1. A method of interconnecting a fastener having a threaded shank and a

substrate which is softer than said fastener shank, said method comprising the steps of:

(i) if necessary, creating a recess in said substrate,

(ii) causing a flowable hardenable substance to flow into said recess, and

(iii) after said flowable substance has hardened, screwing said shank into said hardened substance in said recess.

2. The method as claimed in claim 1 including the further step of:

(iv) screwing said shank through said hardened substance in said recess and into the substrate adjacent said recess.

3. The method as claimed in claim 1 or 2 including the further step of:

(v) creating a lead in indentation in said hardened substance at the intended location of said shank.

4. The method as claimed in claim 3 wherein said lead in indentation is formed prior to said hardenable substance hardening.

5. The method as claimed in any one of claims 1-4 wherein said flowable

hardenable substance is a plastic polymer.

6. The method as claimed in claim 5 wherein said polymer is an injection

mouldable plastic.

7. T e method as claimed in claim 6 wherein said injection mouldable plastic is selected from the class consisting of polypropylene and polyvinylchloride.

8. The method as claimed in any one of claims 1 -7 wherein said substrate is selected from the class consisting of timber, timber substitutes, and timber derivatives including particle board and medium density fibreboard.

9. The method as claimed in any one of claims 1-8 wherein said fastener has self- tapping threads.

10. The method as claimed in any one of claims 1-9 wherein said recess is

substantially cylindrical or frusto-cylindrical.

11. An article of furniture having a first portion thereof fabricated from a substrate and including a recess substantially filled with a hardened flowable hardenable substance, wherein a fastener having a threaded shank has said shank screwed into said hardened substance in said recess.

12. The article as claimed in claim 11 wherein said substrate is softer than said fastener shank and said fastener shank extends through said hardened substance in said recess and into the substrate adjacent said recess.

13. The article as claimed in claim 11 or 12 wherein after hardening of said

flowable hardenable substance but before screwing said shank into said substance, said substance includes a lead in indentation at the intended location of said shank.

14. The article as claimed in claim 13 wherein said lead in indentation is formed prior to said hardenable substance hardening.

15. The article as claimed in any one of claims 11-14 wherein said flowable

hardenable substance is a plastic polymer.

16. The article as claimed in claim 15 wherein said polymer is an injection

mouldable plastic.

17. The article as claimed in claim 16 wherein said injection mouldable plastic is selected form the class consisting of polypropylene and polyvinylchloride.

18. The article as claimed in any one of claims 11-17 wherein said substrate is selected from the class consisting of timber, timber substitutes, and timber derivatives including particle board and medium density fibreboard.

19. The article as claimed in any one of claims 11-18 wherein said fastener has self-tapping threads.

20. The article as claimed in any one of claims 11-19 wherein said recess is substantially cylindrical or frusto-cylindrical.

21. The article as claimed in any one of claims 11-20 wherein said fastener

attaches a second portion of said article to said first portion.

22. The article as claimed in claim 21 wherein said second portion is selected from the class consisting of a table leg, a bull nose, and joinery mongery including hinges, handles and latches.

Description:
FURNITURE FASTENER INTERCONNECTION

Field of the Invention

The present invention relates furniture and, in particular, to a method of interconnecting a fastener to a substrate and an article of furniture including such fasteners.

Background Art

Furniture is traditionally made from timber or substitutes for timber, many of which are derived from timber and include particle board and medium density fibreboards. Fasteners such as screws, normally with self-tapping threads on the shank of the fasteners, are used to secure together different portions of timber or timber substitutes, or are used to secure hinges, handles, latches, and the like, which might be termed joinery mongery, to the timber or timber substitutes.

Often the timber substitutes, in particular, are coated with an exterior hardwearing layer such as those sold under the trade marks FORMICA and MELAMINE. Where these coatings or veneers are used, fasteners sometimes extend through the exterior layer. However, in general it is preferred that fasteners be concealed from view since they are regarded as being unsightly, A problem with timber substitutes, in particular, is that they are not particularly strong and thus the load which is able to borne by fasteners which extend into timber substitutes is generally relatively low. In particular, the timber substitute is liable to fail by the body of the timber substitute immediately adjacent the fastener breaking away from the remainder of the timber substitute when an excessive force or load is applied either to the fastener directly, or more usually to the item which the fastener secures. For example, it is well known that the hinges of cupboard doors are likely to be pulled from the wall of the cupboard or the doors themselves as a result of an application of an excessive downward force on a door which swings about a vertical axis.

Genesis of the Invention

The genesis of the present invention is a desire to improve the strength of engagement of fasteners in such articles of furniture. Summary of the Invention

In accordance with a first aspect of the present invention there is disclosed a method of interconnecting a fastener having a threaded shank and a substrate which is softer than said fastener shank, said method comprising the steps of:

(i) if necessary, creating a recess in said substrate,

(ii) causing a flowable hardenable substance to flow into said recess, and

(iii) after said flowable substance has hardened, screwing said shank into said hardened substance in said recess. In accordance with a second aspect of the present invention there is disclosed an article of furniture having a first portion thereof fabricated from a substrate and including a recess substantially filled with a hardened flowable hardenable substance, wherein a fastener having a threaded shank has said shank screwed into said hardened substance in said recess.

Brief Description of the Drawings

Embodiments of the present invention will now be described, with reference to the accompanying drawings in which:

Fig. 1 is a plan view of the underside of a table top in accordance with the first embodiment of the present invention,

Fig. 2 is a cross-sectional view taken along the line II - II of Fig. 1,

Fig. 3 is a similar cross-sectional view taken along the line III - III of Fig. 1 ,

Fig. 4 is a plan view of the underside of another table showing the positioning of two mountings or attachments for the legs,

Fig. 5 is a cross-sectional view taken along the line V - V of Fig. 4,

Fig. 6 is a cross-sectional view taken along the line VI - VI of Fig. 4 but showing a leg inserted into the leg attachment, and

Fig. 7 is a perspective view showing a cupboard door of the third embodiment. Detailed Description

As seen in Figs. 1-3, a table top 1 having an upper surface 2 and a lower surface 3 is illustrated. The table top 1 has a central core 5 formed from particle board, medium density fibreboard, or the like and the upper surface 2 and lower surface 3 are formed from a rigid plastics layer such as sold under the trade marks FORMICA or MELAMINE. Preferably the table top 1 has a moulded plastics peripheral bead 6 which is preferably formed from an injection mouldable plastic such as polypropylene or polyvinylchloride. The bead 6 is moulded onto the table top 1 by placing the table top 1 into a mould and injection moulding the bead 6 in its entirety as single piece. As a consequence, there is good natural keying between the bead 6 and the material of the central core 5.

However, it is desirable, especially in a school room situation, for there to be additional attachment which secures the bead 6 to the table top 1. This is provided by means of protrusions 7 each of which is substantially frusto-cylindrical in shape and fills a recess 8 drilled into the underside of the central core 5, the recess 8 being filled during the injection moulding procedure. Also formed during the injection moulding procedure is a lead in indentation 9 as seen in Figs. 1 and 2 and which provides a convenient, and accurately located, starter point .for a fastener 11 having a self-tapping threaded shank 12. The upper portion of Fig. 1, and Fig. 2, show the protrusion 7 prior to the insertion of the fastener 11 , and the lower portion of Fig. 1, and Fig. 3, show the protrusion 7 after the insertion of the fastener 11.

Preferably, as illustrated, the shank of the fastener 12 passes right through the protrusion 7 and into the central core 5. Because the protrusion 7 is tightly bonded to the central core 5 as a result of the injection moulding process, and the shank 12 has its upper portion tightly bonded with the protrusion 7, so the fastener 11 is much more tightly bonded to the table top 1 as a whole, than would be the case, if, for example the fastener 11 had been passed through the lower surface 3 and thence into the central core 5. Turning now to Figs. 4-6, it will be apparent that the above described technique can also be used to attach legs, for example, to a table top. Illustrated in Fig. 4 is the underside of a table top 21 having two leg attachments 24 which are simultaneously formed with a bead 26 by injection moulding. The leg attachments 24 take the form of short cylindrical protrusions 27 each of which is formed by filling a part circular recess 28 in the table top 21. Each protrusion 27 includes a pair of lead in indentations 29 and a cylindrical blind hole 30. Opposite each lead in indentation 29 is a corresponding elongate cylinder 40 which has a length intended to accommodate the entire shank of a fastener.

A leg 33 is formed from cylindrical tubing 34 and has an annular flange 35 which is welded to the tubing 34. As seen in Fig. 6, two fasteners 41 are each able to be passed through a corresponding aperture 43 in the flange 35 and thereby align the tip of the shank 42 of the fastener 41 with the lead in indentation 29. This accurately locates the flange 35 and the fasteners 41 and the leg attachment 24 prior to the fasteners 41 being screwed home. Once screwed home, the entire shank 42 of each fastener is entirely located within the corresponding cylinder 40 of plastic. This leads to extremely high pull out strengths for the fasteners 41. Furthermore, the flange 35 is compressed against the outer surface of the leg attachment 24. In addition, there is good adhesion between the protrusions 27 and cylinders 40 on one hand and the recess 28 on the other hand so that, as a

consequence, the flange 35 is held more firmly to the table top 21 than would be the case if the fasteners 41 and their shanks 42 merely penetrated the native material of the table top 21.

As a comparison test, a fastener such as 41 was directly screwed into particle board and the pressure applied to it longitudinally to pull the fastener from the board. At a pressure of 100 Kg (approximately 1000 Newtons force) the fastener pulled out taking the particle board adjacent the thread with it. An equivalent test was carried out in relation to the arrangements of Figs. 3 and 6. The fastener resisted a pressure of 300 Kg without pulling out and this was the maximum force able to be applied to the fastener by the testing apparatus, so the force required to pull the fastener out with the arrangements of Figs. 3 and 6 is not known with certainty. Clearly a very substantially improvement over the prior art has been achieved.

Turning now to Fig. 7, in the third embodiment a cupboard door 51 is illustrated which has a peripheral bead 56 and a frusto-cylindrical protrusion 57 substantially as illustrated in Fig. 4. However, instead of being a table leg 33 which is attached to the cupboard door 51, instead a hinge 63 is attached to the cupboard door 51 by means of two fasteners 71. As before, a particularly strong engagement is achieved between the hinge 63 and the cupboard door SI. It will be apparent that the same joining technique can be used in relation to Other items of joinery mongery such as cupboard door handles, door latches, locks and the like.

The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. For example, in some instances the shank of the fastener can pass completely through the protrusion where only light loads are to be experienced and thus a less expensive fastener having a shorter shank can be utilised. Alternatively, for heavier loads, a longer shank and a deeper protrusion (such as cylinder 40) can be used so that the shank of the fastener does not reach the weaker native material but remains entirely within the plastic cylinder 40.

The term "comprising" (and its grammatical variations) as used herein is used in the inclusive sense of "including" or "having" and not in the exclusive sense of

"consisting only of '.