GB2206615A

GB2206615A - Wall tie of porous tube, extruded adhesive and ram

Info

Publication number: GB2206615A
Application number: GB08810782A
Authority: GB
Inventors: Gene Alfonse Falco
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-05-07
Filing date: 1988-05-06
Publication date: 1989-01-11
Anticipated expiration: 2008-05-06
Also published as: AU1451888A; FR2614912A1; AU612641B2; GB8810782D0; DE3815551A1; GB2206615B; JPS6421139A; CA1302726C

Description

r', (-I ( '..1 1 v,,Luob 1 j MASONRY ANCHOR

DESCRIPTION

The present invention relates to a method and device for anchoring and/or fixing inasonry 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. llere, 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 prior art devices. As will be seen from figure 1, very little adhesive material is extruded between the sleeve 20 and the facade 12. Therefore, insufficient anchoring is created between the sleeve 20 and facade 12.

The foregoing disadvantage arises from the fact that all of the known prior art sleeves are uniformly pervious, i.e., have have a uniform mesh or hole distribution along their length. As a result, as seen in Fig. 2, when the threaded rod 28 is inserted into the sleeve 20, the distribution of the adhesive, along the length of the tube, produces a conical taper indicated generally by the numeral 30 wherein the material moves freely and uniformly toward the leading edge rather than in a significantly radial direction through the sleeve. 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 leading end of the sleeve. As a consequence of the conical pattern 30, it will be noted that very poor contact exists between the sleeve 20 and the facade 12 although it is precisely in this area, that the-maximum adhesion is desired.

Illustrative of the prior art anchoring sleeve, is that shown in HUGEL, U. S. 4,620,406, which shows a sleeve formed of a wire screen having uniform 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 so as to prevent overall movement of the sleeve during c 1 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 diminishel.

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 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 inventiont 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.1AIRY 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 -5compressed 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 provided, w.hich in total, have a path 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 be 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 mass.

Still further, it is preferred that the tube be formed of a cylindrically 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 apparent, that the axial sections may be selected in any number and manner, to conform to the type and size of the masonry structures on which it is used. By such selection, the sleeve can be provided so 30 that selected amounts of adhesive -6material are extruded in selected axial sections within the structure so that the most advantageous and optimal securement may be obtained.

The use of the tapened anchoring pin in the system employing a porous sleeve filled with 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 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 the 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. 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 material may be used provided they exhibit adequate tensile and shear strengths. Various polymer material such as nylons or 30 polyesters would provide excellent 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 5 maximize adhesion.

Full details of the present invention are set forth in the following disclosure and illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF 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 15 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;

1 Fig. 6 is a crosssectional view taken for example, along lines 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 the 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 present invention, as seen in Fig. 4, the method thereof may easily be understood.

As seen in Fig. 4, the invention is embodied in a wire mesh tube or sleeve generally indicated by 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 introduction of the anchoring rod 42 such as the straight rod shown in Fig.

3 or the tapered 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 masonry hole 18 and which enables the tube to be secured against axial movement under the force of the 1 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 poros'ity. 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 in the prior art devices. A rod-like ram 42 and/or stud element is inserted in 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 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.

is 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 movementt 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

1 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 44, shown in Fig. 4 as being aligned at 41 with the void 14 between facade 12 and block 10, 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.

The dimensions illustrated herein may of course, be varied depending upon the need for each particular application. Resh 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 multipervious 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 ran, 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 brick 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.

aeration hardens 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 diameter and threaded on its outer surface 54, the cross-sectional configuration as illustrated in Fig. 6, wherein the annular space between the ram and the porous sleeve is full of voids or empty spaces 56 and wherein no or relatively small quantities of adhesive is located. As a result, there is little engagement of the rod 52, with the mesh sleeve 32, and a poor anchoring system with the adhesive mass is created (See Fig. 4). These voids or empty spaces 56 are formed by the axial movement of the rod 52 through the plastic or soft moldable adhesive 30 causing cavitation and within the mass. Ultinately when the mass 30 the voids 56 become fixed. The thixotropic adhesive mass 30, noted earlier as being self-supporting even in the uncured state, will cure without coalescing into a cohesive mass. In fact, upon insertion of the rod 52, the rod's level of contact with adhesive is the highest it will get and will remain set at this height during the entire curing process.

The disadvantage shown 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 taper of the pin 60 is uniformly formed and increases along its length from the front end 62 along its central axis to the rear end 64. The smaller 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 -14length of the tapered pin 60 will, of 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 utass 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. 1To 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 -0 -15 extrusion of the mass through the pores in the sleeve accomplished.

The tapered configuration to the anchoring pin 60 uniquely harmonizes with the fluid dynamics i.nvolved during the ram installation of a central fastening element, producing maximized adhesion to surrounding 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 C stainless steel threaded cylindrical rod in conjunction with an epoxy gel filled screen tube is usually specified. Typically, pull tests of this configuration result in screen failure at less than 2,000 pounds tension. The reason for consistent screen failure in such installations is a poor distribution of epoxy between the cylindrical stud and the inside diameter of the screen tube (too much epoxy has axially displaced, leaving a substantial void along 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 invention 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 tension depending 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).

-16 Typically tapered pins may be manufactured by double disc grinding of cut- to-length threaded studs at a taper rate of 1/C diameter per 7-1/2" of length. This taper achieves the desired adhesive flow characteristics. Stainless steel, which is generally used, offers the greatest combination of performance and marketability due to its corrosion resistance).

The hardenable mass compounds are generally twopart 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 along the entire tapered length. This gives the user the impression of additional mechanical hold by epoxy infiltration of the remaining thread depths.

The tapered pin 60 can if desired be effectively used without the mesh or screen in situations where the contractor chooses to inject directly onto masonry substrates containing one or more bores or holes (rather than pre-filling screen tubes as is generally done). This method presents the contractor with a tradeoff. On the one hand, he saves the cost of the screen tube, while on the other hand, he has to fill each hole blindly on location, running the risk of over or under filling substrates.

The present tapered pin addresses the fluid dynamics of thixotropic epoxy relative to the area betwen 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 in driving the thixotropic epoxy 1 11 1 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 the epoxy between the sleeve and the substrate, masonry.

Claims

29 1. Apparatus for performing, in combination with a hardenable thixotropic adhesive mass, an anchor between two or more masonry el-ements having axially disposed voids or spaces therebetween, comprising an axially elongated perforated tube having a leading end and a trailing end, said tube being restricted at its leading end and open at its trailing end for the insertion of ram means to extrude the adhesive from said tube, said tube being selectively divided along its length into a plurality of porous axial sections, each section having a porosity different from that of its adjacent section, enabling selected distribution of the adhesive in selected areas of the voids or spaces.
2. The apparatus according to Claim 1, wherein said section having the greater porosity-is located at the trailing end of said tube.
3. The apparatus according to Claim 1, wherein said tube comprises a cylinder formed of sheet material provided with openings in each section uniformly distributed about the circumference.
4. The apparatus according to Claim 1, wherein said tube is formed of a cylindrically shaped wire mesh, having a solid impervious plug at its leading end.

1 0 A 1
5. The apparatus according to Claim 1, including an annular band of impervious material selectively located along the length of said wire tube.
6. The anchor according to claim 1, where said ram means comprises an elongated conically shaped tapered pin, said tapered pin displacing hardenable mass substantially equal to its volume thereby maintaining said sleeve completely filled with hardenable mass and ram.
7. The fastening device according to claim 5, wherein said anchoring pin has a taper rate of 1/8" diameter per 7 1/2" of length.
8. The fastening device according to claim 5, wherein said anchoring pin has a substantially smooth surface.
9. Apparatus as claimed in clair. 1, substantially as herein described with reference to Figures 3, 4, 7 and 8 of the accompanying drawings.

ub',is-ried 19813 at Ile Fazer, State Housc. 6671 High Holborn, London WC1R 4TPFarther copies may be obtained froin The Patent Office,