FR2787153A1 - Nut and bolt fastening has end of nut closed by cap which breaks off under pressure from bolt - Google Patents

Abstract

The fastening consists of a nut (1) designed to engage with a male bolt or threaded rod (2), the end of the nut being closed by a cap (5) with a peripheral weak zone which allows the cap to detach when a given pressure is applied to it by the bolt. The weak zone is formed by inner and/or outer circular grooves and it has a diameter equivalent to that of the nut's inner thread (11), while the end of the nut surrounding the cap has a smooth inner surface that acts as a locking ring when the cap is removed. The end of the nut opposite the cap has a base (9) with a convex surface (10) for even distribution of stresses.

Description

The present invention relates to a nut able to cooperate with

  a male threaded element such as a screw.

  The male threaded element is engaged by one of the ends of the nut. The invention will apply particularly to the field of the joinery industry, closures or even

  fences, especially of plastic or aluminum.

  The invention presented here applies to the nuts as such or to other female threaded members filling the

nut function.

  In the field under consideration, the following types of nuts are particularly known:

  - The hexagonal nut which is the simplest and most common.

  The male threaded element passes through it. It is also often associated with a washer for support on the part, with a lock nut for holding in position and tightening and sometimes with a plastic cap allowing to cover it in order

  to improve its aesthetic appearance.

  - The self-locking nut which limits untimely loosening of the threaded connection. Self-locking nuts are the most

  often made by incorporating a polyamide ring.

  - The flange nut which forms a larger bearing surface on the workpiece which allows a larger surface of

  contact while replacing the support washer.

  - The blind nut which does not allow the male threaded element to pass through in order to improve the aesthetic appearance of the nut. The fact that the male threaded element does not open moreover avoids possible attacks by the projecting part of the screw or the stud but limits the possible length of the element

male.

  These different types of nuts have specific advantages but these advantages cannot be found in combination in a single

nut type.

  Thus, in applications where it is both important to have a large bearing surface on the workpiece, a cap nut and a good quality tightening, we do not have

  currently no suitable nut.

  In the particular field of joinery, closures or fences, the nuts currently used have

different disadvantages.

  First, the profiles and hardware used in this area are most often made of polyvinyl chloride (PVC) or lacquered or anodized aluminum. They thus present surfaces of beautiful finishes but fragile. As a result, their surface can be damaged by installation tools (such as

  sockets or pipe wrenches) or during handling.

  The nuts currently used do not avoid all risks of damage, in particular by contact of a tool with the surface.

pieces.

  Another disadvantage of current assemblies using conventional nuts is that they are not flexible use screws

  with respect to common lengths of hardware.

  In fact, the screws are most often produced in common lengths staggered by half a centimeter (30, 35,

mm etc.).

  To achieve an efficient assembly and a good finish. It is necessary both to avoid too much overshoot of the male threaded part beyond the nut and at the same time to respect the conditions of assembly by thread allowing an optimal connection. On this last point, it is not recommended to use a threaded connection whose length is less than

  0.8 times the nominal diameter of the screw.

  The current nuts do not allow to adapt perfectly to these requirements, which often requires the use of particular lengths of fasteners increasing

  substantially the cost price of the assemblies.

  In the case where common lengths of fasteners are nevertheless used, it is often found either a poor connection by threading, or a significant overshoot of the male threaded element outside the nut, which can be damaging in terms of

  aesthetic or even constitute dangerous projections.

  Another drawback of the nuts currently used in the field of joinery, closures or fences, is that they are not suitable for taking into account the dimensional variations linked to the change in temperature which are

  important for plastic or aluminum materials.

  Consequently, there is a variation over time in the tightening of the assembled elements, which can lead to either

  deformation of the elements, i.e. unscrewing the nuts.

  The object of the present invention is to remedy the drawbacks of the systems currently used and to produce a nut which has good flexibility of use in the

  field of assemblies for carpentry, closings or fences.

  One of the first objects of the invention is to combine the

advantages of existing nuts.

  To do this, the nut according to the invention allows blind use while allowing, if necessary, use in the form of a through nut. The nut according to the invention may also have means ensuring braking of the assembly by threading and good quality support.

on the coin.

  Another object of the invention is to produce a removable cap on the nut. In doing so, the nut can, at will, be blind or even through. This possibility increases the flexibility of using the nuts since it allows, if necessary, to remove the cap in order to make the nut cooperate with

  a male threaded element of greater length.

  The invention also aims to adapt to different standards of fastening length. To do this, it presents

  a specific depth under the cap.

  Furthermore, the nut according to the invention makes it possible to produce

  a salient element in one piece, therefore in one color.

  Other goals and advantages will emerge during the

  description which follows which is however only given as

  indicative. The nut able to cooperate with a male threaded element, such as a screw, engaged by one of its ends is characterized by the fact that it comprises a removable cap closing off its other end. The invention may be presented in the following embodiments: The cap has a peripheral zone of mechanical weakness capable of yielding under the action of a force of value

  predetermined to uncover the other end of the nut.

  The peripheral zone has a circular groove

  inner and / or an outer circular groove.

  The peripheral zone of weakness is circular and its

  diameter is equivalent to that of the thread.

  The force under the action of which the peripheral zone of weakness is capable of yielding is produced by the male threaded element when one continues its screwing after its abutment on the

cap.

  The height under cap h of the thread of the nut includes an additional margin to the length of assembly by thread considered to be ideal, said margin corresponding to the current dimensioning pitch of the lengths of screws, certainly allowing the use of a standard length screws without removing the cap while guaranteeing an assembly length by

ideal thread.

  The nut has a base with a convex profile for supporting the nut on a part allowing the stress distribution

applied to the part.

  The nut thread includes a self-terminating part

  tapped in material removal when screwing the male threaded element, ensuring the braking of the assembly by threading The terminal part is formed by threads of reduced depth compared to that of the first threads, achievable

according to the standard.

  The attached drawings are given as indicative and non-limiting examples. They represent a preferred embodiment according to the invention. They will allow

easily understand the invention.

  Figure 1 shows a profile view of the nut according to the invention and a male threaded element in the form of a screw end. Figure 2 is a sectional view of the nut Figures 3 and 4 respectively illustrate a use

  blind and use cap removed.

  As shown in Figure 1, the nut 1, according to the invention, commonly has an internal thread 11 as well as an outer part 13 allowing in particular the cooperation with a setting tool. To this end, the outer part 13 can

  be, for example, hexagonal as shown.

  The nut 1 can be produced according to the invention, in different materials. In particular, in applications related to closings, joinery or fencing, it will be advantageous to form a nut 1 of plastic material and in particular

polyamide.

  The nut 1 cooperates with a male threaded element 2 shown

as a screw in Figure 1.

  The thread 1 of the nut 1 and the male threaded element 2 is assembled by engagement of the male threaded element 2 by

  one 3 of the ends of the nut 1.

  As shown on the drawing boards in Figures 1

  at 3, the other end 4 of the nut 1 has a cap 5.

  This cap 5 preferably made of the same material of the nut 1 is removable. It obtains the closure of the end 4 but allows, if necessary, to produce a nut 1

crossing as in figure 4.

_ -

  To allow the removable nature of the cap 5, it

  this will preferably include a peripheral zone of weakness 6. It is in this zone that, in the event of pressure greater than a predetermined value, the cap 5 will rupture. To form the peripheral zone of weakness 6 and thus create a preferential rupture zone, the peripheral zone 6 may include an inner circular groove 7 or a

outer circular groove 8.

  As shown in Figures 1 to 3, the peripheral area 6 can both have an inner circular groove 7

  and an outer circular groove 8.

  The peripheral zone of weakness 6 essentially aims to yield under the action of the male threaded element 2 when

  it continues to be screwed beyond the threaded part 11.

  Thus, the male threaded element 2 is engaged, at first. At the end of screwing, its end abuts under the cap 5. If additional screwing is necessary, further screwing of the male threaded element 2 generates the

  rupture of the peripheral zone of weakness 6.

  To implement these steps, a peripheral zone of shape weakness is preferably used.

  circular and with a diameter equivalent to that of thread 11.

  The peripheral zone of weakness 6 can, moreover, be

  consisting of continuous or discontinuous circular groove.

  The nut according to the invention also allows, without requiring the removal of the cap 5, to adapt to

common lengths of hardware.

  Generally speaking, the lengths of screws are established and staggered in steps of 5mm. We thus know commonly, lengths of screws 30, 35, 40mm etc. The depth of the nut 1 under the cap 5 makes it possible to accept a male threaded element 2 whose length is greater than the ideal length commonly calculated according to the

__1 _ _

  formula 0.8 times the value of the nominal diameter of the threaded element

male 2.

  According to the example where the current lengths of fastenings are staggered every 5mm, a margin of the order of 5mm will be produced. The following example illustrates the advantage of such an additional margin on the height h of the thread: either a profile with a thickness of 27mm on which it is desired to fix a fitting.

  5mm thick with a 6mm nominal diameter screw.

  In a common case, we should use a screw length

  27mm + 5mm + (0.8 X 6mm) or 37mm.

  To make a good mechanical quality assembly and use common screw lengths, it is then necessary to choose a bolt length of 40mm. With the use of common nut, the choice of a length of 40mm fasteners leads to a significant overshoot of the end of the male threaded element 2 beyond the nut. In the present case, taking into account the additional margin presented by the nut 1 under the cap, the use of a length of screws of 40 mm is authorized without any excess of the male threaded element 2 beyond the nut 1. The adaptation of the value of the additional margin to the staggering of the lengths of current fasteners makes it possible, without fail, to use a current length of fasteners in combination with the nut 1 according to the invention while ensuring an assembly by good mechanical quality thread (at least 0.8 times the nominal diameter of the screw) without exceeding the threaded element

male 2 beyond the cap 5.

  As illustrated on the drawing boards, the nut 1 according to the invention may comprise, in a particular embodiment, a base 9 ensuring a large bearing surface

of the nut 1 on a part (14).

  As shown in Figure 3, the base 9 may have a convex profile 10 allowing a better distribution of

  stresses applied by nut 1 to part 14.

  In this way, the nut 1 damages the part less when

  its support and especially during its implementation.

  The base 9 also makes it possible to form a protection between the part and a fitting tool used for cooperation with the

external part 13.

  This avoids scratches on the part at the periphery

of nut 1.

  Given the problems of expansion of the constituent elements of assemblies in the field of carpentry, closures or even fences, the problem of tightening and holding in position of the nut 1 with respect to the threaded element

male 2 is fundamental.

  To solve this problem, the nut 1 according to the invention may have a thread 11 comprising a self-tapping end portion 12 without removal of material during the screwing of

the male threaded element 2.

  The elastic deformation of the terminal part 12 ensures the

  braking of the assembly by thread.

  As shown in Figure 2, the end portion 12 may be formed of threads whose depth is reduced compared to that of the other threads of the thread 11. This reduction in depth may, moreover, be increasing the more one moves

towards the cap 5.

  The invention thus presented allows a perfect adaptation of the nut 1 to these conditions of use. This adaptation is particularly important in the case of assembly of parts

  formed from aluminum or plastic such as PVC.

  From an aesthetic point of view, the nut 1 has many advantages since it ensures the formation of the terminal part of the bolts without requiring the use, for example, of caps above through nuts. In this way, the visible part of the fixing on the nut side only consists of the nut 1 which can be made of a single material and of a single color, possibly matched with that of the part 14 and different from

  that of the male threaded element 2 such as a screw.

TC-

REFERENCES

  1. Nut 2. Male threaded element 3. First end 4. Second end 5. Cap 6. Peripheral weakness zone 7. Internal circular groove 8. External circular groove 9. Base 10. Convex profile 11. Thread 12. Terminal part 13 External part 14. Room h. Thread height

Claims (9)

  1. Nut (1) able to cooperate with a male threaded element (2), such as a screw engaged by one (3) of its ends, characterized in that it comprises a removable cap (5) closing off its other end (4) 2. Nut (1) according to claim 1 characterized in that the cap (5) has a peripheral zone of weakness (6) mechanical capable of yielding under the action of an effort of predetermined value in order to discover the other end (4) of the nut. 3. Nut (1) according to claim 2 characterized in that the peripheral zone (6) has a circular groove   inner (7) and / or an outer circular groove (8).   4. Nut (1) according to any one of claims 1 to   3 characterized in that the peripheral zone of weakness (6) is circular and   that its diameter is equivalent to that of the thread (11).   5. Nut (1) according to any one of claims 2 to   4 characterized in that the force under the action of which the peripheral zone of weakness (6) is capable of yielding is produced by the male threaded element (2) when one continues its screwing after its abutment on the cap (5).   6. Nut according to any one of claims 1 to 5   characterized in that the height under the cap (h) of the thread (11) of the nut (1) includes an additional margin to the length of assembly by thread considered to be ideal, said margin corresponding to the current dimensioning pitch of the lengths of screws, allowing for sure the use of screws of current length without removing the cap (5) while guaranteeing a length ideal thread assembly.   7. Nut according to any one of claims 1 to 6   characterized by the fact that it comprises a base (9) with a convex profile for supporting the nut (1) on a part allowing the distribution of the   constraints applied to the part.   8. Nut according to any one of claims 1 to 7   characterized by the fact that the thread (11) of the nut (1) comprises a self-tapping end portion (12) without removal of material when the male threaded element (12) is screwed ensuring the braking of the assembly by thread 9. Nut according to claim 8 characterized in that the end part (12) is formed of threads   reduced depth compared to that of the first fillets. You