FR2530306A1 - Self drilling, self tapping, removable screw, and its implementation. - Google Patents

Abstract

The object of the present invention is a hollow self drilling, self tapping screw and its simple and rapid implementation via an appropriate mandrel. The screw is characterised by its hollow shape, the existence of a head 10 which allows it to be removed, that of studs allowing the screw to be driven by the flutes of a drill and cutting lips 11 at the end facilitating its penetration in the material to be assembled. The mandrel itself is formed from a drill 14 and an adjusting ring 15. This invention finds its application in the field of removable assemblies in general.

Description

The present invention relates to a removable self-drilling screw, self-tapping and its implementation.

The technical sector of the invention is that of dismountable assemblies.

To assemble two or more pieces by means. of a screw, a certain number of operations are conventionally required
you have to trace
point
drill
tap
j and finally assemble the parts by screwing the screw into its
housing.

This procedure can take several minutes depending on the nature of the assembly.

In order to reduce this implementation time, a certain number of self-drilling and self-tapping screws have been developed but have limited use linked to their design:
These screws are generally usable only for assemblies where the screw
emerges into the void; blind assemblies being more delicate
to achieve.

In addition, the stuffing of the chips created by the end in the form of
screw forest, limits the length of drilling and tapping to which
only millimeters.

Finally, the mechanical implementation of the screw requires the use of
sophisticated and therefore expensive chucks.

These main limitations are related to the fact that the screw is full
chip removal. drilling and screw guiding are
difficult.

The present invention aims to remedy these drawbacks by adopting a
screw designed and implemented in an original way.

As shown in Figure 1, showing one of the embodiments of
the screw in longitudinal section, the screw is of conical or hollow cylindrical shape with the following characteristics:
Mark II: The left end of the screw can have two
or-several cutting lips allowing dega
manage the passage necessary for the penetration of the
screw; -
We also see in Figure 2, representing the screw seen on the right
Reference 10: The head of the screw, as its thread are obte
:. - - naked by rolling or stamping and its shape
can be conical, cylindrical or other and the em-
preprint allowing its disassembly can be
cruciform or other.

Reference 13 Two screw drive pins are formed
- when forming the screw.

FIG. 3, showing the screw in lonsitudinal section, illustrates the mounting of the screw on a mandrel formed by a forest 14 and an adjusting ring 15.

The diameter of the forest corresponds; to the required clearance, to the inside diameter of the screw. #: - - .- - - -
The two pins illustrated in Figure 4 (Ref. 13) engage in the grooves for evacuating wood shavings 14
Once: once in Piaee, the screw lets protrude; ^ the forest by a few millimeters, thanks to the adjustment made by means of the ring -15
Figure 5 illustrates the implementation of the screw during assembly:
The forest mounted on a drill chuck (Item 16), begins by penetrating the parts to be assembled then the cutting lips described in Figure 1 (Item 11) come into play by evacuating their shavings with those of the forest through the grooves of the latter (Rep. 17).

 The tapping is normally done by crushing the material (s) by the threads of the screw, the latter being rotated by the pins (see fig. 4 Rep. 13).

When the screw head comes into contact with the surface of the part to be assembled,
the opposing couple increases rapidly and when it reaches its maximum,
that is to say when the screw head is pressed or embedded on the surface of the part to be
assemble, the pins are erased either by a # rachment, or by permanent deformation
nente.

 The forest thus released from the pins turns crazy and can be removed from the screw.

 The assembly is carried out and the screw can be removed if necessary thanks to the shape of its head.

 The assembly operation will only take a few seconds.

High-speed implementation from a mandrel with an ali system
fast mentation is also planned.

Claims (7)

 whether or not it leads to the other side of the assembly.  a portable drill for all kinds of assemblies, as the screw  self-tapping, removable and easily implemented by means  l - Screw characterized by its hollow shape allowing it to be self-drilling, 2 - Screw according to claim 1 characterized in that its implementation can  be made from a simplified mandrel characterized by the use of a  adjustment ring 15 fitted onto a commercial drill 14, this drill  supporting and driving the screw.  cutting 11 facilitating the penetration of the screw.  that the end opposite its head is provided with one or more edges 3 5 - Screw according to any one of the preceding claims, characterized in  4 - Screw according to any one d, es- previous claims characterized in  that two pins # 13 allow its training on the drill 14, in  leaning on the grooves of the drill and disappear when it reaches its  final position. 5 - Screw according to any one of the preceding claims, characterized in  what it is removable. 6 - Screw according to any one of the preceding claims, characterized in  what it is made from a metal or plastic tube  rigid. 7 - Screw according to claim 6 characterized in that the screw is made  in high speed by rolling or stamping.