Note: Descriptions are shown in the official language in which they were submitted.
TRANSLATION 2 0 9 2 7 0 0
Device for Attaching an Object to a Lightweight Material Wall
The invention concerns a mounting device for att~rhing an object to a
lightweight material wall, with an insert which features a cavity for
receiving a fastener, a tool blade which protrudes beyond the insertion
end of the insert and has a drilling point for making in a lightweight
material wall a cylindrical rough hole for receiving the insert, and a
self-tapping external threading, and with a setting tool which in rota-
tionally fixed fashion can be inserted in the cavity of the insert.
EP-Bl-165-674 describes such a mounting device with an insert featuring
on its insertion end an opening and a tool blade protruding beyond the
insertion end of the insert provided with a self-tapping external
threading. The tool blade makes it possible to create in a lightweight
construction material, during the setting, with the aid of the tool
blade arranged on the front end of the insert sleeve a rough hole for
the external threading of the insert. As a fastener used as a screw is
twisted in upon setting the insert in a lightweight construction materi-
al with a material thickness smaller than the length of the insert
provided with the external threading, the front end of the screw forces
the tool blade sideways out of the way. Therefore, the prior insert not
requiring a rough hole can be used only if its length exceeds the thick-
ness of the lightweight construction material. An application involving
- 2 - 2 092700
merely a blind hole, and not a through-hole, is not possible because of
the necessary sideways escape movement of the tool blade.
Known from ~E-C-'2 419 111 is an insert for fastening an object in a
lightweight material wall, the insert being closed on the front end and,
upon creation of a cylindrical rough hole, turned into the latter with
the aid of a power drill. As the insert is screwed into the cylindrical
rough hole, its external threading cuts itself into the soft lightweight
construction material, leavir.g the material between threads intact. This
enables an anchoring free of expansion pressure, of a fastener which
upon setting of the insert is screwed into its axial cavity for mounting
an object.
US-A-3 289 290 describes a process and a device for setting in one oper-
ation a mounting screw which requires a cylindrical rough hole to screw
into. The mounting screw, for instance a wood screw, is for that purpose
provided with a longitudin~l bore extending through it all the way,
through which a usual drill bit chucked in a power drill is slipped in
order to drill through the longitudinal bore of the screw a hole into
the mounting substrate. Once the rough hole has been made, a screwdriver
fitted in the chuck along with the drill bit engages the head of the
screw, so that the latter can be screwed into the rough hole just com-
pleted, without requiring the retraction of the drill bit in a first
operation and the spin-in of the screw in a second operation.
2092700
- 3 -
Basing on this prior art, the problem underlying the invention
is to provide a device of the initially discussed type which
in a material-saving way allows a quick and simple assembly
in lightweight construction materials of any thickness without
preparing a rough hole.
This problem is inventionally solvèd in that the tool blade
on the setting tool is fashioned as a flat slat blade and can
be advanced with its drilling point, through the cavity of the
insert, beyond its insertion end.
Since the setting tool protrudes with its blade beyond the
insertion end of the insert, it is possible, for one, to
produce with the tool blade, in a single operation, first a
rough hole as the setting tool rotates, which rough hole is
in the course of its creation engaged by the insertion end of
the insert, which due to the rotary movement cuts a threading
with its external threading. Upon retraction of the setting
tool, for another, a fastener - specifically a screw - can be
turned into the vacated cavity of the insert, without its
advance being affected by a tool blade provided on the insert.
In a broad aspect, the present invention relates to mounting
device for fastening an object on a lightweight material wall,
with an insert which features a cavity for receiving a
fastener, a tool blade which protrudes beyond the insertion
end of the insert and has a drilling point for making in a
lightweight material wall a cylindrical rough hole for
receiving the insert, and a self-tapping external threading,
and with a setting tool which in rotationally fixed fashion
can be inserted in the cavity of the insert, characterized in
that the tool blade is fashioned on the setting tool as a flat
slat and can be advanced with its drilling point, through the
cavity of the insert, beyond the insertion end of the insert.
~*
~ ,
- 3a - 2 Og2 700
Suitable developments and designs of the invention derive from
the subclaims and the following description of an embodiment
of the invention with the aid of the drawing, which shows in
Fig. 1, a perspective view of a setting tool according to
the invention;
.~
4 2092700
Fig. 2, a side elevation of the insert according to the invention;
Fig. 3, a view of the rear end of the insert illustrated in Fig. 2,
left;
Fig. 4, a vi~ew of the front end of the insert illustrated in Fig. 2,
right, viewed in axial direction;
Fig. 5, the insert with the inserted setting tool, the toolholder of
which is chucked in a power drill and whose tool blade pro-
duces during the setting operation a rough hole in a light-
weight material wall;
Fig. 6, a sectional view along line VI-VI in Fig. 5;
Fig. 7, the insert and setting tool after setting in the lightweight
material wall, partly cut away, as a side elevation;
Fig. 8, the insert set in the lightweight material wall after a
mounting screw for attachment of an object to the light-
weight material wall has been turned in; and
Fig. 9, a cross section of the insert illustrated in Fig. 8,'showing
the position of the mounting screw in the cross-slotted
cavity of the insert.
Shown perspectively in Fig. 1 is a setting tool 1 which with its-hexago-
nal toolholder 2 can be fitted in the chuck of a power drill. Molded to
the hexagonal toolholder 2 is an adapter 3 from which protrudes a tool
blade 4. The adapter 3 is tapered so as to provide a better grip in its
assembly. ~hile the toolholder 2 and the adapter 3 consist preferably of
plastic, the tool blade 4 consists of a metal of sufficient hardness and
wear resistance.
2092700
The tool blade 4 is fashioned as a relatively flat slat of constant
thickness and constant width and extends into a point S of triangular
design with a rounded point, its material thickness ~irini ~hing forward-
ly, so that the tool blade 4 with its point 5 assumes a dagger type
appearance.
The rounded point 5 also has a shape enabling the driving or retraction
of cross-slotted screws with the setting tool 1. This makes it possible
to use the setting tool 1 also as an emergency screwdriver.
The tool blade 4 has a material thickness of, e.g., 1.3 mm and a length
of about 40 mm. The adapter 3 may have a length of 10 mm, the toolholder
2 one of 15 mm.
The setting tool 1 serves the setting of an insert 7 illustrated in Fig.
2 and consisting of plastic or die-cast zinc. The insert 7 features a
cylindrical core section 8 through which extends a slot 9 visible in
Fig. 2. The slotted cylindrical core section 8 extends into a conic
section 10 extending on the rear end of the insert 7 into a collar 11.
The cylindrical core section 8 and the conic section 10 are surrounded
by a coarse-pitch threading 12 fashioned as a self-tapping external
threading, so that the insert 7, as it is screwed into a bore in a
lightweight construction material, cuts a threading in which the insert
7 finds a hold without expansion pressure.
- 6 - 2092700
The self-tapping threading 12 ends at the point marked 13, before the
collar 11 on the rear end of the insert 7, and dwindles on the front, or
insertion, end 14 of the insert 7 with an ever-diminishing thread
height, as can b'e seen best from Fig. 4.
Fig. 4 also shows that in the spire of the threading 12 adjacent to the
insertion end there are several recesses 15 provided, forming several
cutting edges 6 which facilitate the tapping of the threading 12 in a
lightweight construction material, specifically a plasterboard panel.
The conic area lO solidifies the plasterboard panel at the rear end of
the insert 7, enabling thereby higher retention forces of the mounting
device.
Fig. 3 shows a view of the rear end of the insert 7 and the collar 11,
the latter being ring-shaped in plan view. Visible both in Fig. 3 and
Fig. 4 is a cavity 16 cross-slotted in cross section, which in axial
direction extends through the insert 7. The cross-shaped cavity serves
after the setting of the insert 7 to receive a fastener, particularly a
screw 27 (Fig. 8), which with is threading is allowed to tap into the
plastic surrounding the cavity 16.
The cavity 16 consists of a wider flat slot 17, which in Fig. 2, 3 and 4
extends nearly horizontally, and of a narrower flat slot 18, which in
Fig. 3 and 4 extends almost vertically. The wide flat slot 17 and the
narrow flat slot 18 traverse the insert 7 from the rear end on the
collar 11 to the insertion end 14.
- 7 - 20927 00
The wider flat slot 17 has a width corresponding to the core dia~eter of
the threading 12, respectively to the outside diameter of the cylindri-
cal core section 8. Therefore, the wide flat slot 17 in the cylindrical
core section.8 forms the already mentioned slot 9 forming a first shank
19 and a second shank 20, which by the turns of the surrounding thread-
ing 12 are mechanically so stabilized that the slot 9 will not result in
any appreciable weakening of the insert 7 in its front area.
The width of the tool blade 7 corresponds to the width of the wider flat
slot 17, and-thus to the diameter of the cylindrical core section 8.
This can be seen especially distinctly in Fig. 5.
Fig. 5 shows a lightweight material wall 22, specifically a plasterboard
panel, in which the tool blade 4 has produced a rough hole 21 which is
cylindrical nearly all the way, after the setting tool 1 has been
slipped - starting at the collar 11 - into the flat slot 17 of the in-
sert until the adapter 3 bears on the collar 11 and after the setting
tool 1 - with its toolholder 2 fitted in the chuck 23 of a power drill -
has been rotated.
During the rotations generated with the aid of the power drill, the
point 5 of the setting tool 1 first digs through the upper layer, spe-
cifically a cardboard layer, of the lightweight material panel 22. Next,
it traverses the lightweight construction material 22 and emerges again,
as can be seen from Fig. 5, on the opposite side of the lightweight
material panel 22.
- 8 - 2 0 927 0 0
Shortly thereafter, the insertion end 14 of the cylindrical section 8,
its diameter corresponding to the width of the tool blade 4, proceeds
into the just prepared rough hole 21 in the lightweight construction
material 22 as s`oon as the first turn of the threading 12 engages with
its cutting edges 6 the material of the lightweight panel 22, so that
the insert 7 produces a threaded hole in it.
Fig. 6 depicts in a section along line VI-VI of Fig. 5 the geometric
ratios and shows particularly how the width of the tool blade 4 entirely
occupies the wider flat slot 17 and reaches up to the surface of the
cylindrical core section 8, while the threading 12 produces a threading
which reaches up to the dotted circle 24.
MAk;ng the threading in the light weight material panel 22 is completed
after a few revolutions, and the insert 7 is screwed in as shown in
Fig. 7. Instead of a power drill, also a cross-tipped screwdriver can be
used to carry out the setting operation, for which reason the toolholder
2 features an axial depression for the positive insertion of a cross-tip
screwdriver. A conic recess 25 in the tool blade 4 is so arranged in the
axial depression that the rim of the recess and the point of the cross-
tip screwdriver will engage well.
Fig. 7 shows particularly also the ratio of the length Ll of the insert
7 to the length L of the tool blade 4 protruding out of the adapter 3.
The length of the tool blade 4 outside the adapter is about 1.5 to 3
times as large as the length of the insert 7.
-
9 2092700
Once the assembly state illustrated in Fig. 7 has been reached, the
setting tool 1 can be retracted out of the insert 7 screwed into the
lightweight material panel 22, in order to attach an object 26 with the
aid of a screw 2;, which by means of the setting tool 1 can be twisted,
through the object 26 to be fastened, into the cavity 16 of the insert
7. Once the screw 27 has been spun in, the fastening of the object 26 to
the lightweight material panel 22 is obtained as illustrated in Fig. 8,
without expansion pressure.
Fig. 9 shows a cross section through the lightweight material panel 22
and insert 7 along with screw 27, detailing how the threading 28 of the
screw 27 is cut into the plastic material between the wide flat slot 17
and the narrow flat slot 18.
From the above description it follows that the insert 7 can be set in a
single operation without requiring a separate operation for preparing
the rough hole 21. The result is a simple and quick assembly at low
material expense.
