Note: Descriptions are shown in the official language in which they were submitted.
~302726
CP(SP9) Falco (For ~ppln.)
The present invention relates to a method and device for
anchoring and/or fixing masonry wall elements.
In much of masonry construction, two or more elements must
be anchored or "pinned" together to strengthen them, either
during initial construction, during subsequent repair, or during
attachment of ancillary elements to the masonry structure. One
such typical application, which also illustrates the prior art
method and the curently used device is shown in Figs. 1 and 2.
Here, a concrete block wall construction 10 is faced with a brick
facade 12, and a void 14 exists either by design or due to normal
shift of the foundation due to failure of original brick tie
elements. Under prior art techniques, a hole 18 is drilled
through both the facade 12 and the concrete block 10 into which a
tubular hollow screen sleeve 20 is inserted. The sleeve 20 is
restricted but not fully closed at its leading end 22 by
overlapping the edge of the screen and is opened at its trailing
end 24. Upon insertion, or even after insertion, the sleeve 20
is filled with a hardenable adhesive or cementatous mass 26.
Prior to the hardening of the mass 26, a metal rod 28 or anchor
is inserted into the sleeve so as to exert ram pressure on the
adhesive mass forcing the material through the sleeve and
radially outward.
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An anchor involving the sleeve 20, the adhesive mass
26, the facade 12 and the concrete block 10, is only partially
effective with the ~rior art devices. ~s will be seen from
~igure l, very little adhesive material is extrucled between the
sleeve 20 and the facade 12. ThereEore, insu~ficient anchoring
is created between sleeve 20 and ~acade 12.
The foregoing ~isadvantage arises ~rom the fact that all of
the knowll prior art sleeves are uniformly pervious, i.e., have a
uniform mesh or hole distribution alon~ their entire length. As
a result, as seen in Fig. 2, when the threaded rod 28 is inserted
into the sleeve 20, the ~istribution of the adhesive, along the
lenc3tll o~ the tube, I)roduces a conical taper indicated generally
by the numeral 30 wherein the material moves freely and uni~ormly
toward tlle leading ed~e rather than in a significantly radial
direction throll(3h the s~eeve. It is only when the pressure
against the slug of adhesive material within the sleeve becomes
so great, that the material is forced in any degree radially from
the sleeve. This, occurs only toward the leadin~ end o~ the
sleeve. ~s a conse~luence of the conical pattern 30, it will be
noted that very poor contact exists between the sleeve 20 and
tlle facade 12 althou~3h it is precisely in this area, that the
maximum adhesion is desired.
Illustrative o~ the prior art anchoring sleeve, is that
shown in IIUGEL, U. S. 4,620,~06, which shows a sleeve formed of a
wire screen having unirorm mesh size along its entire length.
This device also includes a collar at its trailing end which is
adapted to make force fit contact with the bore formed in the
masonry ~o as to prevel)t overall movement of the sleeve during
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the extrusion of the hardenable mass. Uniform mesh or perforated
sleeves are also shown in U. S. Patent 4,528,792; U.S. Patent
1,646,457. In British application to 2,112,487 an anchoring
sleeve like socket is formed having uniformly disposed open slots
or perforations therein. The sleeve is filled with a adhesive
material which is caused to effervesce in situ expanding through '
the slots or holes. This type of anchor is not subject to ram
forces created by the anchoring rod.
In general, the masonry fastening systems to which the
present invention relates, employ thixotropic, or gel-like
hardenable masses such as polyester resins, epoxies, etc., which
are capable of being supported in the uncured state by the porous
sleeve or a simple hole, prior to and during the insertion of the
anchoring ram. The curing properties, as well as the adhesion
and flow characters of such hardenable masses vary, depending
upon the specific recipe and composition thereof. Nevertheless,
an ordinary threaded rod, when rammed into the sleeve filled with
the uncured hardenable mass, displaces substantially more of the
hardenable mass than the actual volume of the threaded rod.
Thus, virtually all of the hardenable mass becomes displaced
axially through the pores or holes in the sleeve leaving only a
negligible amount of the hardenable mass between the threaded rod
and the inside diameter of the sleeve. Thus, adhesion to the
threaded rod is substantially diminished.
It is an object of the present invention to provide an
anchoring system in which a more uniform and better contact of
adhesive is provided with the masonry than is currently possible,
particularly when it is intended to attach or reattach the
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building facade to the base concrete block. This is absolutely
necessary where no trailing end attachment is desired, such as a
nut, roset, or other flange device.
It is a further object of the present invention, to provide
an improved anchoring system in which a selective distribution of ~
adhesive along the length of the anchoring sleeve is made. It is
the particular object of the present invention to provide a
screen sleeve for use with a hardenable adhesive and an anchoring
bolt, for obtaining a brick to brick, block to block or brick to
block masonry securement. (or any other masonry or stone
elements).
It is a particular object of the present invention to
provide an anchoring pin which when inserted into a porous sleeve
or connecting hole, filled with a thixotripic adhesive, which
element does not displace substantially more of the adhesive,
than its own volume, thereby insuring improved adhesion between
the anchoring element and the masonry.
SUM~IARY OF THE INVENTION
In accordance with the present invention, a method and
device is provided for anchoring masonry structures together,
comprising the use of perforated tubular anchoring elements
having a leading end and a trailing end. The tubular element is
restricted at its leading end to prevent passage of adhesive
material and open at its trailing end for the insertion of a
hardenable mass of adhesive material. The adhesive material, is
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compressed by a ram-like anchoring pin which acts to extrude the
adhesive radially from the tube. The tube is selectively divided
along its length into at least two axial sections, in one section
perforations are providecl, which in total, have a l~ath of less
resistance to radial extrusion than in the other section, thus
enabling selection of relatively different amounts of adhesive
material to be extruded from the selected lengths. Preferably,
the section with the least resistance to radial extrusion is to
~e located at the trailing end of the tube wherein, the initial
ram action occurs.
Preferably, the anchoring pin has a tapered or
conical-shape, with its smaller diameter at its forward end and
gradually increasing in cross-sectional area to its rear end, the
anchoring pin being insertable into the sleeve, through the
hardenable mas 5 -
Still further, it is preferred that the tube be formed of acylindrically shaped wire screen and the difference in porosity
and therefore, resistance to radial extrusion of adhesive, be
provided by varying the mesh size in different axial sections of
- the tube.
It is preferred that the leading end of the tube be closed
completely as by setting a solid metal slug at the leading end.
It will be a~parent, that the axial sections may be selected
in any number and mallner, to conform to the type and size of the
masonry structures on which it is used. By such selection, the
sleeve can be providecl so that selected amounts of adhesive
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material are extruded in selected axial sections within the
structure so that the most advantageous and optimal securement
may be obtained.
The use of the tapered anchoring pin in the system employing
a porous sleeve filled with a hardenable (curable) adhesive mass ~
is greatly advantageous as it enables a simpler, easier and less
costly method of establishing a unitary anchor. When the smaller
diameter end of the tapered pin is inserted into the open end of
the porous sleeve filled with a hardenable uncured mass, it does
not displace substantially more than its own volume because the
gradual increase in cross-sectional area of the pin increasingly
takes up the void which would be created during insertion of a
cylindrically-shaped element.
Since the fluid dynamics of the tapered pin results in the
displacement of substantially its own volume, more of the
hardenable mass is maintained within the sleeve between the
anchoring element and the porous sleeve. There is therefore
better adhesion of the hardenable mass to the anchoring element.
Also, since the hardenable mass, the porous sleeve and the
tapered pin are all now integrally engaged, the strength of the
entire anchor is improved, and moisture infiltration and stress
are significantly reduced.
Preferably, the tapered pin is made of metal, such as
stainless steel, and with a substantially smooth outer surface.
However, other types of materials may be used provided they
exhibit adequate tensile and shear strengths. Various polymer
materials such as nylons or polyesters would provide excellent
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strength characteristics at a lower production cost than metal
threaded rod. The surface texture of the tapered anchoring
element may also be varied depending upon the bond
characteristics of the hardenable mass in order to maximize
adhesion.
Full details of the present invention are set forth in the
following disclosure and illustrated in the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS:
In the drawings:
Fig. 1 is a section view of a masonry construction showing
the use of the prior art method and device,
Fig. 2 is a view of the conventional prior art screen sleeve
showing the normal distribution of the hardenable adhesive under
action of the rod ram,
Fig. 3, is a view of a wire mesh tube embodying the present
invention;
Fig. 4, is a view similar to that in Fig. 1 showing the wire
mesh tube of the present invention in use;
Fig. 5, is a perspective view of the conventional prior art
threaded anchoring rod;
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Fig. 6 is a cross-sectional view taken for example, along
line 6-6 of Fig. 1 showing the normal distribution of the
hardenable adhesive under action of the prior art threaded
anchoring rod;
Fig. 7 is a perspective view of the tapered anchoring pin of
the present invention; and
Fig. 8 is a cross-sectional view similar to that of Fig. 6
taken along lines 8-8 of Fig. 3 showing the improved distribution
of the hardenable adhesive under the present invention.
By turning first to the description of the wire mesh tube
for carrying out the presellt invention, as seen in Fig. 4, the
method thereof may be easily understood.
As seen in Fi~3. 4, the invention i8 embodied in a wire mesh
tube or sleeve yenerally indicated by the numeral 32, being
closed at its leading edge by a solid slug 34, preferably
soldered or welded into place, and open at its forward end 36 for
the introductioll of the anchoring rod 42 such as the straight rod
shown in Fig. 3 or the tc.pered rod of the present invention shown
in Figs. 7 and 8 as desired.
The leading end may be restricted without providing a slug
or welded closure as for example, by crimping or pinching the
leading end. Extending forwardly from the trailing end 36, is a
tab 38 which enables the tube 32 to be manually held for
insertion into the masollry hole 18 and which enables the tube to
be secured against axial movement under the force of the
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ultimately inserted anchoring ram. In accordance with the
present invention, the tube 32 is divided into at least two axial
sections, namely a forward section 32a and a trailing section 32b
each of different mesh size and therefore of different
perviousness or porosity. The forward section 32a has a smaller
mesh size and thus a smaller open area than the trailing section '
32b. The two sections 32a and 32b are joined, in the embodiment
of Fig. 3 by a lapping seam 40 wherein the rear end of the
smaller mesh section 32a overlaps the leading end of the larger
mesh section on the exterior surface. The lap seam 40 is
preferably welded, braised or otherwise joined together.
Preferably, the trailing section 32b (coarser mesh) does not
extend too deeply axially along the tube 32.
The use of the device as shown in Fig. 3 is illustrated in
Fig. 4. The tube 32 is initially filled, in the normal manner,
with adhesive material to the extent that no voids or air spaces
are found in the filling. The filled tube is then inserted
through a close fitting bore 18 (hole 18 should be small enough
in diameter so that the extruded adhesive is sufficient to fill
the hole) and passed beyond the void 14 formed between the
concrete block 10 and the brick facade 12 and fully through the
concrete block 10, as is the prior art devices. A rod-like ram
42 and/or stud element is inserted into the trailing end. The
ram 42 may be smooth or embossed as required for greater adhesion
or holding power.
The ram 42 is inserted from the trailing end 36 toward the
leading end 34 forcing the adhesive material 26 within the sleeve
toward the forward end 34. Because the mesh at the trailing
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section 32b is substantially more coarse than that at the leading
section 32a, the gel-like adhesive material is more easily
extruded radially in the area of the facade 12, as at 46 even
though the ram force and pressure duration is relatively small.
The larger holes in the coarse mesh section 32b at the
trailing end 36 compensates for the short period of time and
pressure duration, effected by the ram 42 in moving through the
trailing end, as opposed to the larger period of time and
pressure duration effected by the ram 42 at the leading end 32a
of the sleeve. As a result, a shape distinctly different from a
cone and of more uniform volume of the adhesive mass along the
length of the sleeve is extruded than otherwise possible with the
conventional sleeve. As the ram 42 continues its movement, the
adhesive material is pushed toward the leading end 34. Because
of the more restricted wall 34 at the leading end of the tube,
the axial flow of the material is inhibited thereby, the adhesive
material backs up within the tube 32 causing it to flow readily
in a radial direction rather than in the axial direction. This
provides a significant radial flow of adhesive between the outer
surface of the tube 32 and the solid surface of the concrete
block 10, as seen at points 48 and 50 as well as within the
hollow chambers 15 of the concrete block.
Consequently, the adhesive forms a toggle between the
masonry elements and greater adhesive contact is obtained between
the brick facade 12 and the anchoring tube 32, as seen in Fig. 4.
Compare this with the substantially lesser contact made in the
prior art as seen in Fig. 1. This increased contact is effected
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without any need for additional adhesive material. Therefore,
the adhesive is more effectively utilized.
If one wants to further insure against waste of adhesive
material, and provide areas of non-extrusion along the length of
the tube 32, an impervious band 44, of metal, plastic tape or
other means is wrapped about the sleeve. The band A4, shown in
Fig. 4 as being aligned at 41 with the void 14 between facade 12
and block ln, acts to blank out certain areas from extrusion of
adhesive, the position of the band or bands are selected,
depending upon the nature of the structure to be anchored.
In a typical application such as a brick-tie repair, the
tube of the present invention will be approximately 8 inches long
having 6 1/2 inches at its leading end constructed by a 20 x 20
inch mesh weave of .014 inches diameter stainless steel wire.
The remaining 1 1/2 inches at the trailing end is constructed by
a 14 x 14 mesh weave of .017 inches diameter stainless steel
wire. The lap seam is welded to join the two sections with the
20 mesh material lying exterially of the 14 mesh material. The
tube, in order to accept a 3/8 inch ram and for insertion in a
1/2 inch hole, is formed using a .390 inch diameter welding
mandrel. The tab at the trailing end can be made of any
material, mesh or solid, being dimensioned in size to enable the
user to hold on to the sleeve while it is being filled, and to
secure the sleeve flush with the outside of the facade so that it
is not axially movable during the ram extrusion process. Once
the anchor is completed, the tab can be bent and stuffed into the
hole, and later mortared over to blend with the surrounding
masonry.
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The dimensions illustrated herein may of co~lrse, be varied
depending upon the need for each particular application. ~esh
sizes specified are for a thixotropic adhesive paste, common to
most epoxies and polyester resins. Mesh sizes may also be varied
depending upon the viscosity and/or thixotropy of the adhesive.
Further, rather than using a wire mesh screen, a cylindrical tube
formed of sheet material may be employed which is provided with
holes, perforations, slots or foraminous openings in different
discrete axial sections, having different open area sizes, rather
than mesh. The tube may be formed of metal or plastic materials.
The concept of the present invention is the use of a multi-mesh
or multi-pervious sectioned tube in which discrete, axial
sections have differently distributed openings or mesh sizes,
which will achieve by a non-uniform axial distribution of hole
sizes, mesh, etc., a uniform or electively non-uniform axial
distribution of adhesive so as to obtain more desirable and
selective contact in the process of structural pinning and/or
anchoring.
A further advantage of the present invention arises in
combination with the ram, in that the ram or anchoring rod more
beneficially combines with the adhesive and forms a more integral
part of the anchor, capable of absorbing and carrying loads
placed on it by the briclc and facade structure and/or other
exterior facade attachments. In addition, the added adhesive at
the trailing end increase contact with the ram minimizing any
loosening effect that may be created by the load conditions.
~3027Z6
It has been found that when the ram 42 ~Fig. 3~ is formed in
accordance with the prior art, as illustrated in Fig. 5, namely
an elongated solid cylindrical rod 52 of uniform dianeter and
threaded on its o~ter surface S4, the cross-sectional
distribution of the hardenable adhesive mass takes the
cross-sectional configuration as illustrated in Pig. 6, wherein
the annular space between the ram and the porous sleeve is full
of voids or empty s~aces 56 and wherein no or relatively small
quantities of adhesive is located. As a result, there is little
enyagement of the rod 52, with the mesh sleeve 32, and a poor
anchoring system Wit}l the adhesive mass is created. (See Fig. 4).
These voids or empty spaces 56 are formed by tle axial movement
of the rod 52 through the plastic or soft moldable adhesvie 30
causing cavitation and aeration withirl the mass. Ultimately when
the mass 30 hardens, tlle voids 56 become fixed. Tle thixotropic
adhesive mass 30, noted earlier as being self-supporting even in
the uncured state, will cure without coalescing into a cohesive
mas6. In fact, uUon ~nsertion of the rod 52, the rod s level of
contact with adhesive is the highest it will get and will remain
set aL tllis l-eight durin(3 the entire curing process.
The disadvantages sllown with the use of the prior art
ram-rod devices is overcome by the present invention as
illustrated in Figs. 7 and 8. In the present invention, an
anchoring pin 60 is provided, having a tapered or conical shape.
The taE~er of the pin 60 ifi uniformly formed and increases along
its length from the front end 62 along its central axis to the
rear end 64. Tle fimaller diameter end 62 is at the forward end
with respect to the direction of insertion into the sleeve 32.
The widest diameter end 64 is of course, at its rear end. The
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length of the tapered pin 60 will, oE course, approximate that of
the tubular mesh sleeve 32 into which it is to be inserted or
lengthened so as to extend from the face of the masonry. Thus,
the length as well as the diameters of the pin can be selected to
conform to the application in which it is used.
It should be noted that if the taper is too slight, the
beneficial effect is lost and if the taper is too great, not
enough hardenable mass is displaced radially to fill the annular
space between the ram and the surfaces of the bore in the
masonry.
Preferably, the tapered pin 60 is made of metal, such as
stainless steel. It may be made of other materials having
sufficient tensile and shear strength for the intended purposes.
Nylon and similar polyesters may be used. The surface of the
tapered pin is preferably left substantially smooth, although it
may be textured or provided with suitable layers for better
adhesion to the hardenable mass. Threads or gross working of the
surface is not necessary, thus their expense can be eliminated.
Thus as seen in Fig. 8, when the tapered pin 60 of the
present invention is used, ie., inserted ram-like into a sleeve
32 filled with hardenable mass 30, the cross-sectional flow of
the mass is full and complete along the entire length of the
sleeve. No voids or empty spaces are created, the mass does not
cavitate and there is complete contact and adhesion between the
pin, sleeve and mass along the entire sleeve. Since the tapered
pin does not displace substantially more than its volume, voids
are not created and consequently, a more uniform displacement and
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extrusiorl o~ the mass through the pores in the sleeve is
accom~lished.
The tapered configuration to the anchoring pin 60 uniquely
harmonizes with the fluid dynamics involved during the ram
installation of a central fastening element, producing maximized
adhesion to surroundillg surfaces and a sufficient mushroom effect
in voids.
The same basic fluid dynamics apply for all sizes up to at
least 1-1/2" diameter. In a typical application involving
stabilization of a brick facade over block wall with a void, a
3/8 x ~" stainless fiteel threaded cylindrical rod in conjunction
~tith an epoxy gel ~ille~ screen tube i5 usually specified.
Typically, pull tests o~ this configuration result in screen
failure at less than 2,000 pounds tension. The reason for
consistent screen fa1lure in such installations is a poor
dlstribution of epoxy between the cylindrical stud and the inside
diameter of the screen tube (too much epoxy has axially
di~placed, leaving a subsLantial void alony the length of the
cylindrical central fastening element and the inside diameter of
the screen tube. (See Figs. 5 and 6). In using the tapered pin
of the present inventiorl in lieu of for the 3/8 x 8" stainless
steel threaded stud, the same pull tests have an average yield of
approximately 3,000 - 5,000 pounds,t,,e,nsion dependin~ on the
density of the masonry block chosen (now, failure actually takes
place in the cement block rather than the screen due to the added
involvement of the central anchoring element to the overall
anchor performance).
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Typically tapeeed pins may be manufactured by double disc
grinding of cut-to-length threaded studs at a taper rate of 1/8"
diameter per 7-1/2" of length. This taper achieves the desired
adhesive flow characteristics. Stainless steel, which is
generally used, offers the c3reatest combination of performance
and marketability due to its corrosion resistance).
The hardenable mass compounds are generally two-part
epoxies which offer excellent adhesion to metal and masonry
surfaces. Additionally, the process of double disc grinding of
pre-cut threaded rods does not completely obliterate the thread
alonc3 the entire tapere~ length. This gives tl~e user the
impression of additional mechanical hold by epoxy infiltration of
the remaining thread deptlls.
The tapered pin G0 can if desired be effectively used
without the mesh or screen in situations where the contractor
chooses to inject directly into masonry substrates containing one
or more bores or l-ol~s (rather than pre-filling screen tubes as
i~ ~enerally done). Tl~; r, method presents the contractor with a
trade-off. On the one hand, he saves the cost of the screen
tube, while on tlle other hand, he has to fill each llole blindly
on location, runnil-cJ tlle risk of over or under filling
substrates.
The present tapered pin addresses the fluid dynamics of
thixotropic epoxy relative to the area between itself and the
screen. It eliminates trapped air throughout its anchor length
in the area mentioned, thus adding its strength to the overall
fastening. It also aids itl driving the thixotropic epoxy
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radially, due to its wedged shape. The tapered pin, when used
jointly with the multimesh screen sleeve, adds to the effect
obtained by the sleeve in promoting a more uniform distribution
of epoxy between the sleeve and the substrate, masonry.
