POST ANCHOR AND POST COMPRISING THE SAME

TIGE D'ANCRAGE DE BLOC SUPPORT ET BLOC SUPPORT DOTE DE CETTE TIGE D'ANCRAGE

English Abstract

Disclosed is a post anchor (1) comprising two final sections (11, 12), one
(11) of which can be introduced into a post (10) while the other one (12) is
used for fixing the anchor (1) to or in another element. The section (11) that
can be introduced into the post represents a drill bit section (11) which is
used for introducing a bore (20) into the post (10) in a substantially stress-
free manner. The drill bit section (11) in the bore (20) is provided with
essentially no axial clearance and is preferably embodied as a screw bit. The
drill bit section (11) has a first smaller drill core diameter (31) in a first
zone (31) bordering the tip thereof while having a larger drill core diameter
(32) in a second zone (32) located closer to the other section (12) in the
longitudinal direction thereof (13).

French Abstract

L'invention concerne une tige d'ancrage (10) de bloc support constituée de deux segments terminaux (11, 12), l'un (11) des segments étant introduit dans un bloc support (1) et l'autre segment (12) étant destiné à être fixé sur ou dans un autre élément. Le segment (11) introduit dans le bloc support est un segment de forage (11) permettant de pratiquer, d'une manière essentiellement exempte de copeaux, une forure (20) dans le bloc support (1). Le segment de forage (11) situé dans la forure (20) et ne présentant pratiquement pas de jeu axial est de préférence une mèche à bois à simple spirale. Le segment de forage (11) comporte, dans son orientation longitudinale (13) et dans une première zone (31) adjacente à sa pointe, un premier diamètre de forage (31) de faible dimension et, dans une deuxième zone (32) plus proche de l'autre segment (12), un deuxième diamètre de forage (32) plus grand.

Claims

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Claims
1. A post (1) having a post anchor (10) connected with said
post and comprising two end sections (11, 12), where one section
(11) extends into the post (10) and the other section (12) is
intended for fastening on or in another element, wherein the
post (1) comprises a drillhole (20), wherein one section (11) is
a drill bit section (11), having in a first segment (31),
adjacent to its tip, a smaller drilling core diameter (31) and
having in a second segment (32), arranged nearer to the other
section (12), a larger drilling core diameter (32), wherein the
drillhole (20) has substantially no radial play with said drill
bit section (11) for arranging the section (11) introduced in
the post (1) in the drillhole (20) in the post (10) in a
substantially stress-free manner.
2. The post (1) as claimed in claim 1, characterized in that
an adhesive is in the free space between the drill bit section
(11) and the drill hole (20) in radial and/or axial direction.
3. The post (1) as claimed in claim 1 or 2, characterized in
that the drill bit is an auger bit (11) in all its segments (31,
32).
4. The post (1) as claimed in one of claims 1 to 3,
characterized in that it is designed in one piece and in that
the other section (12) is a threaded rod and/or in that the two
sections (11 and 12) abut.
5. The post (1) as claimed in one of claims 1 to 4,
characterized in that the bore (20) is made centrally in the
post.

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6. The post (1) as claimed in one of claims 1 to 5,
characterized in that the post (1) is made of wood or of plastic
materials and preferably has a square, elliptical, rectangular
or polygonal cross section.
7. A post anchor (1) comprising two end sections (11, 12),
where one section (11) can be introduced into a post (10) and
the other section (12) is intended for fastening on or in
another element, wherein the section (11) which can be
introduced into the post is a drill bit section (11) for making
a drillhole (20) in the post (10) in a substantially stress-free
manner, which drillhole (20) has substantially no radial play
with said drill bit section (11), characterized in that the
drill bit section (11) has in a first segment (31), in the
longitudinal direction adjacent to its tip, a smaller drilling
core diameter (31) and in a second segment (32), arranged nearer
to the other section (12), a larger drilling core diameter (32).
8. The post anchor (10) according to claim 7, characterized in
that the ratio between the axial length of the first area (41)
having the first drilling core diameter (31) to the area (42)
having the second drilling core diameter (32) is between 1:3 and
1:1 and/or in that the first drilling core diameter (31) is set
between one fourth to one half of the external diameter of the
drill bit (11) and the second drilling core diameter (32) is set
between one half and 4/5 of the external diameter of the drill
bit (11).
9. A method of introducing a post anchor (10) as claimed in
one of the preceding claims 7 or 8 into a post (1) according to
one of claims 1 to 6, characterized in that it comprises the
following steps:

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- drilling a drillhole (20) in the post (1) with the drill
bit section (11) of the post anchor (10),
- introducing adhesive into the drillhole (20) with the drill
bit section (11) inserted so as to take up, by filling, any
remaining radial play and the axial play of the drill bit
section (11) in the drillhole (20), or, alternatively,
withdrawing the drill bit section (11), introducing adhesive
into the drillhole (20) and reinserting the drill bit section
(11) into the at least partially adhesive-filled drillhole (20).
10. The method as claimed in claim 9, characterized in that,
prior to introducing the adhesive, the post anchor (10) is
rotated back by an eighth to a half of a rotation.

Description

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Post anchor and post comprising the same
The invention relates to a post anchor having the features of
the preamble of Claim 1.
A post anchor of this type is known from the prior art, for
example from DE 36 34 266. In that document, a screw-in threaded
rod is adhesively bonded in a corresponding drillhole in a post,
a longitudinal groove being provided on the threaded rod so that
the glue can accordingly be allowed to enter the drillhole
between the threaded rod and the wall of the drillhole.
Another post anchor is known from DE 199 12 815, in which a
threaded spike is provided on a plate which can be placed
against the underside of a post, this threaded spike penetrating
the post during positioning of the post anchor. Provided on the
opposite side of the post anchor is a sleeve with an internal
thread so that an anchor bar can be subsequently screwed in
outside of the post.
In all the proposals of the prior art, even when the threaded
rods are glued iri, there is a problem in terms of the
parallelism of the post anchor and post. This means that the
post anchor does not usually have its center axis lying exactly
parallel to the longitudinal axis of the post. This is an
unwanted property of such a system and a disadvantage when
assembling such post anchor systems on building sites.
In practice, the unit consisting of threaded rod and post is
therefore not, as in DE 199 12 815, put together once on the
building site; instead, this takes place beforehand so that said
parallelism can be achieved to the greatest possible degree
under industrial production conditions.

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Moreover, the connection of metal anchors in wooden posts
usually leaves something to be desired in terms of the force
required to extract the anchors, for example.
Taking this prior art as a starting point, the object on which
the invention is based is to provide a post anchor of the type
mentioned in the beginning which has better parallelism and in
which the fixing is, moreover, better secur_ed against twisting.
This object is achieved according to the invention for a post of
the type mentioned in. the beginning having the features of the
characterizing part of the feature of Claim 1.
A post anchor according to the invention is described in Claim
7.
A method of introducing a post anchor according to the invention
in a post is described in connection with Claim 9.
The invention will now be described in more detail with the aid
of an exemplary embodiment with reference to the drawing. The
single drawing shows a partly sectioned perspective view of a
post together with an inserted post entrance.
The reference number 1 is used to denote a post. The post 1 is
made of wood and has a sauare cross section. Of course, the
cross section may also be shaped differently, being for example
round or elliptical, rectangular or polygonal. The material of
the post 1 may also be chosen from another material only if
these materials are similar to wood within the context given
below. The similarity in question is in particular important for
plastic materials.

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Said post 1 has a longitudinal axis whose orientation here is
indicated by the arrow 2 running parallel to it. The post 1 can
be fastened on a wall or floor surface (not shown in the figure)
with the aid of a post anchor (anchor 10 for short) according to
the invention. The figure shows one moment during the production
of the connection between anchor 10 and post 1 when the anchor
has not yet been fully sunk in the post 1.
10 The anchor 10 is preferably constructed in one piece and as such
comprises at least two different regions 11 and 12. The first
region 11 is made up of an auger bit, this region 11 being
intended to be set into the post 1. The second region 12 can be
designed accordirig to the particular application of the post
anchor; in particular it may thus be a threaded rod section.
This threaded rod section 12, either by itself or by way of a
further section (not shown in the drawing), can be positively
connected to a drive, for example a drilling machine, to enable
the auger bit 11 to be driven into the post 1.
The figure shows, in dotted form, the outlines of a drillhole 20
in which the auger bit section 11 has already been advanced more
than halfway. Instead of using an auger bit which allows chips
cut out of the post to be lifted out, use may also be made of
any other drill bit which makes possible the production of a
stress-free bore, in particular in wood, in which there is no
radial play. Radial play here is to be understood as meaning the
distance 21 between the outside of the drill bit 11 and the
inner wall of the bore 20.
The auger bit 11 extracts chips from the drillhole 20 and at the
same time creates a certain free space in the axial direction,
i.e. along the longi_tudinal axis 13 of the anchor 10, into which

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free space an adhesive can be passed in through the upper
opening 22 of the bore 20 once the drill bit section 11 has been
fully inserted.. Particularly advantageous adhesives are epoxy
resin-based adhesives and polyurethanes. Before the adhesive is
introduced, the anchor 10 may preferably be rotated back by an
eight to a half of a rotation in order to make it easier to pass
in the adhesive. Alternati'vely, it may be completely withdrawn,
the adhesive poured in and the drill bit reinserted.
A drill bit according to the prior art only supports its own
weight and forces are solely applied in the longitudinal
direction, i.e. along the axis 1.3. The post anchor 10 here
receives the bearing pressure. This is true for the threaded rod
section 12 as well as for the drill bit section 11. Therefore
the drill bit section 11 according to the invention is divided
into two different segments, having received the reference
numerals 41 and 42. The two segments are made in one piece. The
drill bit section 11 has first drilling core diameter or central
core 31, followed by a central segment 42 of the drill bit 11,
having a second core diameter 32, bei_ng larger than the diameter
of the first drilling core diameter 31.
In a preferred embodiment the first drilling core diameter 31 is
set between one fourth to one half of the external diameter of
the drill bit 11. The second drilling core diameter 32 is set
between one half and 4/5 of the external diameter of the drill
bit 11. This creates between the two segments 41 and 42 a
discontinuity between the diameters of the drilling cores 31 and
32, respectively. The ratio between the axial length of the
areas 41 and 42 can be, e.g., between 1:4 and 1:1 preferably
around 1:2 for achieving a larger st.iffness of the post anchor
10 without impeding the extraction of the chips due to a larger
core drill diameter.

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Instead of two segments 41 and 42 it is also possible to provide
three segments, wherein the smallest core drill diameter has a
value of one fourth, the second central core drill diameter has
5 a value of one half and the third largest core drill diameter
has a value of 3/4 of the external diameter of the drill bit 11.
It is of course possible to choose different transitions and a
higher number of segments.
Additionally it is possible to use a continuously enlarging
drill core for achieving a steady growth of stiffness of the
anchor 10 in direction of arrow 2.
The threaded rod section 12 comprises two different elements,
the threaded rod as such and the drill chuck support. The
threaded rod section 12 and the drill chuck support can be
positioned one behind the other on an axis 13, but it is also
possible to adapt the side surface of the threaded rod section
12, e.g. providing a groove, to create a drill chuck support
within this section.
At location 33 the drill head has a slightly larger diameter
then the drill core 34.
The drill bit according to the invention ensures axially correct
fitting, allowing the arichor 10 to be well centered in the post
1. The prior art according to DE 199 12 815 employing the spike
results in a displacement of the material of the post 1 and thus
in stresses therein.. The auger bit 10 produces a stress-free
bore in wood and other comparable materials.
The length of the anchor 10 depends on its field of application.
For a post 1 having a diameter or cross-sectional dimensions of

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from 5 to 10 centimeters, given a diameter of the auger bit 11
of between 6 and 10 millimeters, a customary total length of the
anchor may be between 10 and 70 centimeters. Preferably, this
length is divided in half between the drill bit part 11 and the
threaded rod part 12. Of course, it is also possible for the
threaded rod 12 or the auger bit 11 to be shorter or longer than
the respective other section. It is also possible to provide a
connection element (not shown in the drawing) between the auger
bit 11 and the threaded rod 12 (or a flat rod without a thread).
This may be an outer hexagonal section or a disc which is
oriented radially with respect to the longitudinal axi.s.
The anchor 10 according t:o this invention provides a simple,
very secure anchor device which is able to be centered and which
is correctly aligned axially, this anchor device 10 being driven
into the post 1. beforehand within a storage area or during the
production of said post. Alternatively, the post anchor 10 may
be set into the posts 1 provided on a building site once on
site.
The diameter of the drill bit section 11 of the post anchor 10
can be chosen between 5 and 18 millimeters and the total length
of the post anchor 10 can be chosen between 10 and 100
centimeters, wherein said length is preferably divided equally
between the drill bit section 11 and the other section 12.
The scope of protection is in no way intended to be limited by
the preceding description showing an exemplary embodiment and
shall apply only to the claims which follow.

Representative Drawing