Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to an anchor device
for use in materials such as concrete, blocks, and certain
types of stone.
Background of the Invention
A well known form of anchor for concrete
employs a shank having a tapered expansion portion in its
inner end. An axially movable or wedge collar formed
of two pieces of metal is arranged around the -tapered
portion and can be expanded outwardly by applying tension
along the axis of the anchor. The collar is then wedged
outwardly against the concrete or masonry material by the
tapered portion.
One form of such an anchor is shown in Canadian
Patent No. 766,~93, issued to AGO. McCulloch on September 5, 1967.
One of the problems of that type of anchor was
the tact that the collar was formed of two or more
separate pieces, which were held in position initially
by means of adhesive tape or the like. There was always
the possibility for the adhesive tape to become dislodged
or damaged, and the collars might simply fall off. When
introducing the anchor into a bore hole, in other than
ideal conditions, there was also a tendency for the
collars to become loosened and lost.
A more serious disadvantage was the fact that
the anchor is usually used with some form of threaded
attachment means at its outer end. This may take the
form of a male thread, or may take the form of a socket,
these two being the most popular forms of this type of
anchor.
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In order therefore to apply the expanding
tension along the axis of the anchor, it is necessary
for something such as a nut, threaded rod or the like
to be attached to the outer end of the anchor. However,
in this type of anchor there was no structure to prevent
rotation of the entire anchor.
If this occurred, then the threaded fastening
device at its outer end could only be tightened up with
the greatest difficulty.
An improved form of anchor is shown in Canadian
Patents 899,669 issued -to R. Seetaram on May 9, 1972 and
953,958, issued to JO Seetaram on September 3, 1974.
In this type of anchor the wedge on the collar
is formed of a single piece of metal, and the tapered
expansion portion is formed with some form of collar
engagement surfaces either in the form of a flattened
portion, or a bed or button or groove. The collar also
had outwardly extending tongues for engaging the sides
of the hole in the concrete
The collar was thus hold by the concrete against
rotation. The collar in turn through its engagement with
the surfaces on the tapered portion, held the shaft
against rotation.
This device was a considerable improvement both
in the fact that the collar was made of one piece of
metal so that it could not become lost, and also because
it was much easier to tighten up when a threaded fastening
device was attached to the outer end.
However, it is difficult to manufacture the
engagement surfaces and the collar to suitable tolerances
in existing mass production techniques, and in practice
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either the tolerances become so slack that the engage-
mint is not sufficiently secure, or alternatively the
costs of production rise to the point where customers
will not purchase the anchor.
An additional disadvantage of -this anchor in
practice was found to be the fact that the tongues
on the collar tended to become deformed as the anchor
was driven into the hole in the concrete. As a result,
they no longer had the same holding capacity, so that
in certain circumstances it was still possible for the
entire anchor to rotate.
For all of these reasons therefore it is clearly
desirable to provide an anchor having a more secure form
of engagement between the collar and the side walls of
. the Holland also having a more secure Norm of engage-
mint between the collar and the tapered portion of the
shaft, so as -to positively resist rotation, and at the
same time, being capable of being manufactured by simpler
mass production techniques, where critical tolerances
do not require to be held to the same degree.
Brief Summary of the Invention
With a view to providing the foregoing features
in a simplified form of anchor, the invention comprises
an anchor having a shank with an inner end and an outer
end, a reduced neck portion formed on the inner end, and
a tapering portion extending from thy reduced neck, and
: having engagement means on the outer end, and a one-piece
expansion collar arranged around the reduced neck portion
on the inner end, and extending partially up the tapered
portion, the collar being formed of a single strip of
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metal having two ends, such collar being formed
with said two ends in end a butting relation, and briny
spaced apart from one another defining an open gap, and
such collar having, in an intermediate portion thereof,
an axial slot extending part way there through and
defining one open end, the open end being directed
towards said tapered portion of said anchor, and there
being at least two generally dome shaped bosses formed
in said collar, extending outwardly therefrom, and
defining a maximum spacing there between greater than the
diameter of the shaft shank of such anchor, said collar
making a loose fit around said reduced neck portion,
and being squeezable there around into a tight frictional
engagement thereon with a short portion of such collar
extending tightly around portion of such tapered portion,
upon engagement of said domelike bosses within the sun-
faces of a bore hole.
More particularly, the invention provides such
an anchor wherein the two ends of such collar, and the
open-ended slot formed in such collar, define at least
fur pointed areas overlying part of such tapered portion,
such pointed areas being squeezable together upon forcing '
of said anchor into a bore hole, and said pointed areas
being thereby forced into engagement with the tapered
portion of said shaft adjacent said reduced neck portion,
thereby providing a good frictional engagement between
said collar and said shaft, whereby to resist rotation
of said anchor.
More particularly, the invention provides an
anchor having the foregoing advantages, wherein the open-
ended slot in said collar defines a predetermined
spacing therein, such that when the collar is squeezed
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together around the reduced neck and the tapered portion
of the shank, the area of the collar adjacent to the
open-ended slot is squeezed inwardly.
The various features of novelty which kirk-
Tories the invention are pointed out with particularity
in the claims annexed to and forming a part ox this
disclosure. For a better understanding of the invention,
its operating advantages and specific objects attained
by its use, reference should be had to the accompanying
drawings and descriptive matter in which there are
` illustrated and described preferred embodiments of the
oven lion .
In the Drawings
.
Figure 1 is a perspective illustration of
an anchor according to the invention;
Figure 2 is a perspective illustration of
the collar of Figure 1 shown in isolation;
Figure 3 is an elevation Al view of a portion
of the anchor, Figure l;
Figure 4 is an elevation Al view of the
anchor of Figure showing the same having been inserted
into a bore hole, with the collar squeezed inwardly;
Figure 5 is an elevation Al view corresponding
to Figure 4 but showing the reverse side, with the
open-sided slot squeezed inwardly deforming the collar;
Figure 6 is an elevation Al view corresponding
to Figure 4, after expansion of the collar;
Figure 7 is a partial section on elevation
of an alternative embodiment;
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Figure 8 is a sectiorlal view of a further
alternate embodiment; arid
Figure is a perspective illustration of a
further embodiment.
As shown generally in Figure 1. an anchor
according to the inventiorl will be seer to comprise a
generally cylindrical shank 101 similar to the shank of a
typical bolt. On an outer end indicated as 121 fastening
means 14 are provided such as the male -threaded portion.
I This may carry a typical nut 16, and washer (not shown)
such as are well known in the art. However any other
threaded means may comprise the fastening means 14, such
as a -threaded socket or the like such as is well known in
the art.
The inner end ox the anchor is indicated
generally as 18. It will be seen -to consist ox a reduced
neck portion 20 owe cylindrical shape, and a progressively
flaring -tapered portion 22. which glares out to the
diameter of the shank portion 10. A right angular
shoulder 24 is formed at the intersection between the
reduced neck 20 and the shank 10.
Wedge means in the form of the collar indicated
as 26 is provided on the reduced neck portion 20. The
collar 26 is shown in more detail in Figure 2.
It will be seen to be a generally cylindrical
shape and comprises a single band ox metal, -~yplcallY
being heavy gauge Haggard steel, with two ends
28-28 spaced apart. An open-ended axial slot 30 is
formed in the collar 26, generally midway between ends 28
which thus places it more or less 180 degrees of arc
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away from the ends 28. The slot 30 does not extend the
full width owe the collar 26, and leaves a bridging
portion 32 ox the collar 26.
Slot 30 defines at its open end a pair of
sharp corners 34. The -two ends 28 similarly define a
pair of sharp corners 36.
A pair of generally dome-shaped abutments
38-3~ are formed on opposite sides ox the collar 26.
Two such dome-shaped abutments are shown. It will
however be appreciated that in a larger collar, on a
larger diameter anchor three or more such dome-shaped
members could be used if desired. The dome-shaped members
are formed merely by pressing impressions or deformations
in the metal, and the metal. is not in fact cut or
severed or weakened at this point. Preferably, the
depressions or domes 38 are formed in such a way that
they are substantially midway between across the width
of the collar 36, so that they leave marginal portions
40 of the collar 38 on either side (see Figure 7) which
is free of deformation.
Collar 26 is of such a width that it extends
from the tight angular shoulder 24, over the full extent
of the reduced neck portion 20 and part way up the
tapered portion 22. The transition between the reduced
neck 20 and tapered portion 22 is shown as a phantom
dotted line in Figures 3, 4, and 5.
The length of the collar 26 is such that it
will not completely encircle the reduced neck portion 20,
so that the two ends 28 define a gap between
. 34 them. In this way the collar 26 makes a loose fit around
the neck 20. In fact the collar 26 can be freely rotated
around the neck 20, prior to insertion into a bore hole.
Figure 3 illustrates -this condition prior to
insertion in the bore hole.
Egress 4, 5, and 6 indicate the operation
of the collar after insertion in the bore hole.
In Figure I, the collar 26 is shown hazing
been squeezed or compressed within the bore hole. This
takes place by the reaction between the domes 38 and the
sides of the bore hole, as the anchor is driven manually
into the bore hole.
It will be noted that the bore hole maces a
snug fit around the shank of the 10 at the anchor, and
as shown in Figure 3 the diametrical spacing Hutton
the outer surfaces of the domes 38 is greater than the
diameter of the shank Lo Thus the dimensions of the
bore hole are such as to apply considerable compressive
force to the domes 38 and to actually cause an inward
squeezing of collar 26. This inward squeezing will be
seen in Figure 4 to have caused closure of the free
ends 38. The free ends 28 are not always completely
closed. They will usually he squeezed closer together
than in the position shown in Figure 3.
Looking at the reverse side, in Figure 5,
the squeezing action of the bore hole in this case
causes a somewhat different action. The open end of
the slot 30 has been squeezed inwardly or closed,
whereas the bridging portion 32 of the collar has
maintained the inward end of the slot 30 open.
Thus it will be seen -that the inner end of the
collar, i.e., the end overlapping the taper 22, has been
squeezed tighter than the outer end, i.e., the end which
is s-till overlying the reduced neck 20.
It will also be observed that by this action,
the two sharp points 34 at the open end of -the slot 30
and the two sharp points 36 defined by the two free ends
28 of the collar 26, have all been forced tightly into
engagement with the tapered portion 22. In fact,
these sharp corners and the inner edge of the collar will
thus bite into the metal of the taper 22, forming a
secure frictional engagement, which is effective to
resist substantial rotative forces.
Similarly, the engagement between the domes 38
and the sides of -the bore hole is of a resilient nature
such that the tighter the fit the better the grip between
the collar and the bore hole. Thus the bore hole grips
the collar, and the collar in turn tightly grips the
shank. The anchor is thus held against rotation.
In order to develop the maximum holding
power, tension is then applied to the outer end of the
anchor 10. Typically this is done by simply tightening
up the nut 16~ Alternatively t axial tension can be
applied by means of a claw hammer or the like, which by
means of leverage can pry the outer end of the anchor
outwardly.
This will cause the tapered portion 22 to be
forced progressively into the collar 26 which will thus
cause expansion. The collar 26 is in turn held in
position in the bore hole by means of the engagement
between the domes 38 and the sides of the bore hole.
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Thus the collar 26 is forcibly expanded into tight
engagement within the sides of the bore hole,
substantially as shown in Figure 6. Clearly the
degree of expansion ox the collar 26 will depend upon
the compressive strength of the material in which the
bore hole is formed which may vary widely from one
type of concrete or material to another.
Substantial pullout forces can be developed
in this way which are found to be highly effective in
practice, and which resist vibration loads, and provides
a highly satisfactory form of fastening in the base
material.
It is also found thaw such anchors are
particularly convenient for workmen to install since
they do not tend to become dismantled or come apart
during handling, and are capable of withstanding rough
usage and even considerable abuse and will still
unction as designed.
Various modifications are possible. For
example, as shown in Figure 7, the shank 10 can be provided
with an internally threaded recess 50, which may receive
a threaded rod or bolt or the like (not shown).
In order to assist in firmly setting an anchor
of this type, an anchor setting device indicated gent
orally as 52 is provided. This comprises a bolt 54,
and a heavy gauge washer or bearing member I which. is
threadedly engaged on the bolt 54.
The setting device 52 provides a convenient
means by which the anchor 10 may first of all be
inserted into the bore hole, and may then have tension
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applied to i-t to partially pull it out -thereby developing
the maximum pullout forces.
This type of anchor is intended to be set so
that -the outer end is flush with the surface of the
receiving material or concrete. In order to do this,
since a certain outward movement takes place during the
setting of the anchor, i-t is necessary that the bore
hole shall be drilled somewhat longer than the length
of the anchor lo The anchor lo is then inserted so
lo that it is in fact inserted with its outer end inwardly
of the outer end of the bore hole. This is achieved
by simply unthreading the bolt I partially from the recess
or socket 50 (as shown in phantom). The bolt 5~1 can then
simply be hammered thereby forcing the anchor lo inwardly
in -the bore hole.
By means of a wrench, the nut 54 is then simply
tightened up, and this applies the axial tension to the
anchor lo which causes the expansion of -the collar as
shown in Figure 6. With a very little practice, it
is possible for workmen to insert and then tension the
anchors Lucy that the outer end of the anchors lo
come substantially flush to the surface of the receiving
material.
This is particularly advantageous in con-
struction of large commercial buildings, where it may
be desirable to apply exterior finishes to the surface
of the concrete after the insertion of the anchors lo
If desired, the setting devices 52 can be let
in position, to prevent the introduction of foreign
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matter into the recesses 50 during the finishing process.
The setting devices 52 can then be removed, and the
recesses 50 are then available for threading of any
suitable attachment. Typically this will be a threaded
rod such as is used for hanging appliances, ducts,
water pipes, sprinkler systems and toe like.
Another modification is shown in Figure 3.
In certain eases much higher pullout forces are required
from a Senegal anchor. In this case tile anchor lo may
have a somewhat longer shank, which is provided with
two tapered portions 22 and AYE, and two collars 26 and
26~.
To precut, an anchor having a double dollar
and double taper of this type will be found to develop
a higher pullout resistance -than an anchor having a
single collar although in practice it is not quite equal
to double the pullout resistance of a single collar.
A further modification is shown in FicJure 9
wherein an attachment means indicated generally as 60
I is provided on the outer end of the shank 10. In this
ease the attachment means simply comprises a tongue
portion 62 having a hole 64. Tupelo, this -type of
anchor is used for hanging suspended ceilings, in which
the ceiling grid is suspended on wire suspension means.
Iiaving described what is believed to be toe
best mode by which the invention may be performed, it
will be seen that the invention may be particularly
derailed as follows;
An anchor compri.xin(3 a shank Wylie an inlay-
end and an outer end, a reduced neck portion formed one inner end, a flaring expansion portion extending
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from the reduced reck, engagement means on the outer end
of such shank, a one-piece wedging collar arranged around
the reduced neck portion on the inner end, and having an
overlapping portion extending partially up the tapered
portion, the collar being formed of a single strip of
metal having two ends and a leading edge and a trailing
edge, such collar being formed with said two ends
arranged end to end spaced apart from one another defining
an open gap, and such collar having, in an intermediate
lo portion thereof, an axial slotted opening extending from
said leading edge part way thrilling and defining one
open end, the open end being directed towards said expansion
portion of said anchor, at least two generally dome-shaped
bosses formed in said collar, extending outwardly there-
from, and defining a maximum spacing there between greater
than the diameter of said chainlike of said anchor, said collar
making a loose fit around said reduced neck portion, and
being squeezable throned into a tight frictional
engagement thereon with said overlapping portion of such
collar extending tightly around such expansion portion,
upon engagement of said domelike bosses within -the surface
of a bore hole, whereby said shank is held tightly against
rotation, said collar being expandable by said expansion
portion upon outward axial movement of such shank, said
collar -thereby wedging against the surfaces of such
bore hole -to secure said anchor.
The foregoing is a description of a preferred
embodiment of the invention which is given here by way of
examples only. The invention is not to be taken as limited
to any of the specific features as described, but comprehends
all such variations thereof as come within the scope of
the appended claims.
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