FR2788569A1 - Fastener for assembling pieces of wood has threaded shank and self-tapping tip of smaller diameter than thread - Google Patents

Abstract

The fastener for assembling pieces of wood, e.g. laminated beams, has a self-tapping portion (f) of smaller diameter than the actual screw. The screw thread may extend over part or all of the length of the fastener. the fastener has longitudinal groove which act as a reservoir for glue if it is required to strengthen the joint. The fastener may be made of wood, plastics or a composite and can be planed flush with the surface of the wood to give a neat appearance.

Description

The present invention relates to a device for assembling elements,

  mainly of wood, solid or agglomerated, of identical and / or various species. The originality of this process consists in making it possible, or not, to dismantle the elements thus fixed together depending on whether they are pre-glued.

  5. and united by the device which is the subject of this patent.

  There are many devices allowing the maintenance between them of wooden elements, screws, nails, staples for example but all are composed of metallic elements, or wooden pegs or plastic but which they have only very poor resistance to "tearing". On the other hand, the high cost of stainless materials and especially corrosion limit

the use of these processes.

  The device according to the invention overcomes these drawbacks.

  Being composed, according to a first characteristic, of threaded wooden rods, which gives it, on the one hand, the ability to be glued, its thread, on the other hand, 15. provides it with excellent resistance to tearing , and finally, the head as the "tapping" part can be turned or not as required and thus give a leveled appearance much more fitting than all systems

  traditionally used, screws and other nails.

  Composed of solid wood, or not, but preferably of wood having 20 good mechanical characteristics, these elements can include a "self-threading" part (f. Fig 1, 2 and 3), which ensures its "self-tapping" "in cylindrical holes and obviously smaller in diameter than the screw itself

said, (f ', Fig. 2 and 3).

  These elements can also include longitudinal grooves, 25. (g, Fig. 1, 2 and 3), real glue tanks used for gluing the thread and this during screwing thus making the assemblies extremely resistant.

  assembled using this process, (G. Fig. 1).

  These elements can be of diameter, section as well as thread

  Varied, the dimensions shown in the drawings are only defined arbitrarily.

  30. As an example, two systems are described below but are not

  obviously not limiting: A-Lag screw, (Fig. 1) and: B- Threaded rod, (Fig. 1).

  In the present description these two elements, A and B are each

  equipped with the "self-threading" system, (f. Fig. 1 and 3).

  A- Lag screw, (A. Fig 1 and 2): More particularly intended to put under pressure 35. wooden elements, (Z, Z1, Z2 AND Z 'Fig. 2), laminated-glued, by

  example and to maintain them, definitively or not, in a chosen position.

  Composed of a head, (a. Fig. 1 and 2), of a diameter greater than the body of the screw, -2- this head is relatively massive in order to resist the effort of screwing and is broken down into three parts : 12.5 mm C. (C. Fig 1), has a slot in its upper part allowing screwing by screwdriver, (d. Fig. 1), this part (C) can be turned and leveled on the outside of the elements once 5.assembled, (i. Fig. 2): D. 12.5 mm. is the part of the lag screw used to hold the head of the screw in a shouldered housing, (Zl. Fig. 2), practiced in the upper element to be joined, (Z. Fig. 2), and inside from which it can perform the rotations necessary to bring the elements to be assembled, (Z, Z2, Z3 and Z '),

  pre-perforated and possibly pre-glued (Fig. 2): E. (Fig. 1 and 2), 12.5 mm.

  10. part of the non-threaded lag screw with a diameter smaller than that of the head, this part of the screw is inserted between the shoulders W. (Fig. 2), made at the bottom of the housing Z1. (Fig. 2), which may, on the other hand, contain glue which will thus be injected under pressure into the grooves (g), and the thread but also around

of the head itself.

  15. The threaded part Y. (Fig. 1 and 2) can be fitted with the "auto-

  tapping ", (f.) composed of a clip or steel ring fixed to the end of the

  screw and tapping the pre-hole, (f ') inside which the screw should be fixed.

  Once in place, the parts that can be turned, (C and f Fig. 1),

  can be leveled giving an excellent "finish" to the whole.

  20. According to this method of fixing, these wooden screws can be screwed at any point on the elements to be assembled, (S Fig. 4) they do not require

  no heavy equipment to ensure their installation.

  Given the frequent need to have to choose from a number of different wood species, this system keeps the 25 elements in place in place, it cancels contractions and contradictory expansions, thermal incompatibilities are controlled by what at all species

  of wood can be used to make these wooden screws.

  According to a particular embodiment, different diameters can be used, from a few millimeters to more than three cm. and more 30. as well as the depth of the grooves and the helical development of the thread. H. (Fig. 3): Horizontal section where we can appreciate the teeth, (h.) Cutting for tapping, as well as the grooves (G and g Fig 1) intended to contain

  the glue needed to glue the pieces to be joined.

  35. According to (Fig. 2), it can be appreciated that the shape of the head of the wooden screws can be split, (d Fig. 1), for its installation using a turner. screw, it can also be of any section, square, triangular, -3- rectangular or of any polygon, (m, n, o, Fig. 2), to ensure

  screwing using a wrench or other pliers.

  According to (Fig. 1 and 2.) the head itself can be banded to avoid

  that it does not break under stress when tightening, (p. Fig. 1 and 2).

  5. B. Threaded rod: More specifically intended to maintain under pressure exerted elsewhere, (v Fig. 3), and definitively or not depending on whether they are glued or not, wooden elements, (Z, Z1 , Z2 and Z 'Fig. 3), laminated

  for example, this rod (B) can be leveled once in place.

  Composed of a threaded wooden rod, this wooden screw has a constant diameter 10. over its entire length, it has in its upper part a slot, (q. Fig. 3), allowing its screwing using a screwdriver for example and may include at its other end a "self-threading" system (f), allowing it to tap the cylindrical hole inside which it is caused to be housed, glued or not. It can also include longitudinal grooves (g), 15. allowing the uniform distribution of glue over all of the tapped surfaces

as well as threaded.

  The "self-tapping" system (f Fig. 1 and 3), is described below by way of example, the choices can be diverse both from the point of view of the profile of the cuts, (h. Fig. 1 and 3 ), that their method of fixing to the screws, they can be 20. banded and / or stapled, they can be of various materials as well as adaptable on drills for the "pre-tapping" of the cylindrical holes inside which are housed wooden screws, glued or not, object of this patent. According to (Fig. 4), we can appreciate the use of the wooden screw of the 25. model A. Lag screw, for the union of elements, (Z, Zl, Z2 and Z ') in the achievement

  a beam, (S.) in glued laminated wood.

  According to (Fig. 4), we can appreciate the use of the wooden screw, model B. Threaded Tiqe, in the holding in place of wooden elements for the realization

  of a beam (S '), in laminated-dcllé.

  30. The device, object d.J this patent, is particularly intended to hold wooden elements, glued or not, between them and this, on thicknesses can be very varied, 40/50 cm. or even more as well as very thin, see a few millimeters, using wooden screws of sections

  meeting mechanical as well as aesthetic criteria.

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Claims (4)

  1. Wooden device allowing the fast, solid and safe assembly of wooden elements such as for example glued laminated beams or others. 2. According to claim 1, the device can be classified into two families:   5. A. said: Lag screw, and B. said: Threaded rod.   3. Device according to claims 1. and 2. characterized in that the   wooden screws can be of section, diameter and various lengths, as well as various materials such as for example: wood, plastic or even in   any armed or unarmed agglomerate.   10. 4. The device according to the preceding claims characterized by the   the fact that the wooden screws can be fitted with the "self-tapping" system, as well as longitudinal grooves allowing the gluing of the thread and the internal thread for a final fixing of the screw once in place 5. The wooden screws can be turned and leveled once in place 15. in order to give a perfectly flat and aesthetic appearance to the exterior surfaces.