Abstract:
For holding brick cladding to a stud frame structure, the brick-tie is a one-piece moulding in plastic. The moulding has a vertical arm, which is secured to the stud by a nail, and a horizontal arm, which is mortar&#39;d between courses of bricks. The nail is located near the junction between the arms, and the junction is chunky enough to be inflexible. The bridge, which spans the space between the bricks and the stud, is also thick enough to be inflexible.

Description:
This invention relates to brick-ties. Brick-ties are used for holding a brick wall, including brick cladding, in the correct spaced relationship with a fixed structure such as a stud wall. 
     BACKGROUND TO THE INVENTION 
     Conventional brick-ties are made of metal, and usually from thin galvanised sheet steel. The steel is usually so thin that the brick-tie is easily able to be bent, or otherwise manipulated, with the fingers. The metal brick-ties provide some resistance to the bricks actually pulling away from the fixed structure of the wall, but they are not very effective. 
     The invention is aimed at providing an improved brick-tie, which overcomes the disadvantages of the conventional brick-tie, and yet which is inexpensive and simple as to its manufacture and use. 
     THE PRIOR ART 
     Previous designs of brick-ties are shown in patent publications U.S. Pat. No. 5,634,310 (Hohmann, June 1997) and U.S. Pat. No. 5,456,052 (Anderson, October, 1995). 
     GENERAL FEATURES OF THE INVENTION 
     The invention lies in a brick-tie, for tying courses of bricks in a brick wall to a fixed structure, and the brick-tie of the invention is a one-piece moulding, in plastic. 
     The brick-tie includes a horizontal arm, which includes an in-mortar portion and a bridge portion. The in-mortar portion is so structured as to be suitable for placement, in mortar, between courses of bricks in a brick wall, and the in-mortar portion is provided with moulded-in surface configuration, for increasing the securement grip thereof into the mortar. One end of the bridge-portion is contiguous with the in-mortar portion. 
     The brick-tie includes a means for securing the other end of the bridge-portion to the fixed structure, and the bridge-portion of the brick-tie is dimensioned to be so inflexible that the bridge-portion cannot, in substance, be bent by finger-manipulation. 
     The flexibility/inflexibility of the bridge portion is an important feature of the invention. When the bridge-portion is inflexible to the degree specified, the bridge-portion can be relied upon to hold the bricks in the correct spaced relationship with the fixed structure. The thin-sheet-metal brick-tie had so little rigidity that the spacing between the bricks and the fixed structure was really not controlled by the brick-ties, except in the grossest sense. There is a requirement for the brick-tie to have some degree of give in the vertical sense, for example because the bricks might settle relative to the fixed structure. But plastic, especially HDPE for example, inherently has enough give in it that this requirement is met automatically. 
     One benefit of the invention is that a plastic brick-tie cannot go rusty. Galvanised steel cannot be relied upon not to corrode, especially over a period of perhaps many decades. 
     When the brick-tie was of thin sheet steel, all aspects of the design of the brick-tie were compromised by that fact. When the brick-tie is moulded in plastic, the designer is free to design the difference areas of the brick-tie according to the different functions each has to perform, and each aspect of performance need not be compromised by the others. 
     In a preferred form of the invention, the brick-tie includes a vertical arm, and an angled junction between the vertical arm and the horizontal arm, and the means for securing the other end of the bridge-portion to the fixed structure comprises a nail-hole, through the vertical arm. Preferably, the nail-hole in the vertical arm is close to the angled junction. Preferably, the portion of the vertical arm that lies between the nail-hole and the angled junction is thick and chunky, and preferably the bridge-portion of the horizontal arm is thick and chunky. Preferably, the nail-hole is smaller than the accompanying nail, and the nail is held gripped by the nail-hole, during transport and sale of the brick-tie. 
     When the fixed structure is a stud wall, the nail-head holds a region of the brick-tie hard against the stud-wall. The stiffer (i.e the thicker and more chunky) the region around the nail-hole, the larger the area that can be said to be held hard against the stud-wall. In the designs depicted herein, the angled junction being thick, it is not just the portion around the nail that is held by the nail, as was the case with the conventional metal brick-tie. In the depicted designs, the whole angled-junction region is held hard against the wall. An important benefit of the invention is that the designer can make the bridge portion of the brick-tie as if it were unitary with the stud—at least in the horizontal direction towards and away from the stud wall. Thus the brick-tie has excellent stiffness horizontally, but permits some flexibility in the up/down sense. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     By way of further explanation of the invention, exemplary embodiments of the invention will now be described with reference to the accompanying drawings, in which: 
     FIG. 1 is a cross-section of a brick-clad wall, which includes brick-ties provided in accordance with the invention; 
     FIG. 2 is a pictorial view of the brick-tie of FIG  1 ; 
     FIG. 3 is another pictorial view of the brick-tie of FIG. 1; 
     FIG. 4 is a side view of the brick-tie of FIG. 1; 
     FIG. 5 is a plan view of the brick-tie of FIG. 1; 
     FIG. 6 is a side view of another brick-tie; 
     FIG. 7 is a plan view of the brick-tie of FIG. 6; 
     FIG. 8 is a side view of another brick-tie. 
    
    
     The apparatuses shown in the accompanying drawings and described below are examples which embody the invention. It should be noted that the scope of the invention is defined by the accompanying claims, and not necessarily by specific features of exemplary embodiments. 
     The wall  20  shown in FIG. 1 is built up from the usual vertical studs  23  of wood. A plywood sheet  24  is nailed outside the studs, and a sheet of plastic or waterproof paper  25  is secured outside the plywood. 
     The brick-ties  26  are nailed to the studs  23 , the nail  27  passing through the paper  25  and through the plywood  24  into the stud. 
     The brick-tie itself is further illustrated in FIGS.  2 , 3 , 4 , 5 . 
     To install the brick-tie  26 , the bricklayer builds up the courses of bricks  28  as required; he places a brick-tie on top of one of the bricks in the last-laid course, while the bricks are still dry, i.e before the application of mortar on top of that course of bricks. He lines the brick-tie up with an appropriate one of the wooden studs  23  and, with the brick-tie resting on top of the brick, drives in the nail  27 . Typically, the brick-ties are applied to every stud (the studs are spaced 16 inches apart, typically), and every five or six courses. 
     With the studs nailed in place, he proceeds to apply mortar  30  over and around the brick-ties, on top of the course  28  of bricks, and proceeds to build up the further courses of bricks. 
     The under-surface  32  of the brick-tie  26  simply rests on the brick  34  underneath. That is to say, there is no mortar between the top of the brick  34  and the under-surface of the brick-tie. The over-surface  35  of the brick-tie  26  is embedded in the mortar  30 , and that surface is provided with ridges  36 . The ridges provide a gripping key between the brick-tie and the mortar. There is no need for ridges in the under-surface  32 , which can be moulded flat. 
     The distance of separation of the inside surface  37  of the brick  34  from the stud  23  (or rather, from the waterproof paper  25 ) is a matter for the local building code; generally, the distance is twenty-five or thirty-five mm. The brick-tie  26  can be is dimensioned to suit. The designer of the brick-tie can provide a one-size-fits-all design, or can provide a number of sizes of brick-tie to suit the different codes. 
     The horizontal arm  40  of the brick-tie may be regarded as being in two portions: an in-mortar portion  29  and a bridge portion  47 . The ridges  36  are provided in the in-mortar portion  29 , whereas the bridge  47  can be plain. 
     The brick-tie  26  also includes a vertical arm  38 . At the junction  39  between the vertical arm  38  and the horizontal arm  40 , the brick-tie includes a buttress  42 . A nail-hole  43  extends through the buttress, i.e extends right through to the back-face  45  of the vertical arm  38 . 
     FIG. 1 also shows the use of a conventional metal-strip type of brick-tie  60 . Such brick-ties are assembled to the studs also by nailing, but the metal strip is so thin that the strip can be bent by hand. The strip is flat when purchased, and is bent to the shape shown either before or after being nailed to the wall. Some builders use the brick-ties  60  as the means for holding the paper  25  in place, thereby avoiding the need to provide additional nails to hold the paper. In this case, all the brick-ties are nailed to the wall before bricklaying is even started. Some builders who do this are conscientious enough to mark off the heights where the brick-ties should be, in relation to the courses of bricks, but others do not bother, and just nail the brick-ties anywhere. Then, when the courses are laid, and the brick-ties come to be fitted between the courses, the horizontal arm of a particular brick-tie might be inches up or down from the nail. In this case, the contribution of the brick-ties to the stability of the wall is questionable. 
     It is pointed out that the conventional design of brick-tie does lend itself to this common type of mis-application. Even when the conventional brick-tie  60  is correctly fitted as to the vertical location of the nail (as in FIG. 1) it will be noted that the brick-tie is rather limited as to the amount of in/out restraint it provides, between the bricks and the studs. If a force arises tending to cause separation of the bricks away from the studs, (or to cause an approach of the bricks to the studs) the conventional ties are too flexible, when acted upon by such forces, with the result that in fact the conventional brick-ties provide only a minimum of effective tying power. They provide good restraint against the bricks moving a large distance away from the studs, but they provide very little restraint against the bricks moving through small distances. 
     It is recognised that brick-ties do have to have some give, but still, the restraint provided by a brick-tie should be better than that of the conventional design, and an aim of the present design to provide that improved restraint. 
     A brick-tie has to have some give in the up/down direction. Nailing the brick-tie to the wall, as described, can never be a highly accurate operation, as to the height of the brick-tie in relation to the course of bricks. Also, the bricks, the studs, and the plywood, are subject to settling, drying out, and to other distortions of various kinds, to the extent that a complete lack of flexibility in the brick-ties might cause problems. 
     Therefore, the bridge portion  47  of the horizontal arm  40  should be thin enough to accommodate a little flexure in the up/down sense. 
     On the other hand, it is an excess of this type of flexibility that renders the conventional metal-strip type of brick-tie  60  less than satisfactory. In a brick-tie, there is an angle between the portion that is nailed to the stud and the portion that lies between the courses of bricks; in the present design that angle is moulded into the structure, whereas in the conventional design that angle is provided by the bricklayer bending the brick-tie with his fingers. In the conventional design, it was this requirement—that the strip be bendable with the fingers in the angle region—that made the strip too flexible in the bridge region. In the present design, the bridge portion can be much stiffer, because the bricklayer does not have to bend the device with his fingers. 
     In the present design, the designer is not compromised by having to make the device so flexible that it can be bent with the fingers. Therefore, the designer can engineer the design to provide the most advantageous degree of flexibility in the up/down sense, without compromise. 
     In the present design, it has been found that a bridge having a thickness of about 5 mm provides the required degree of stiffness. The brick-tie is moulded in high-density polyethylene, HDPE, and is about 25 mm wide. It is important that the thickness be present at least in the stud-end  49  of the bridge  47 , even if the bridge tapers (slightly) towards the brick end  48  of the bridge. 
     The buttress  42  provides some stiffness against flexure of the angled junction  39  between the vertical arm  38  and the horizontal arm  40 . However, providing that stiffness is not the primary purpose of the buttress. Rather, the buttress  42  serves to ensure that the brick-tie is highly rigid in the area around the nail. The brick-tie&#39;s only securement to the stud  23  is via the nail  27 , and it is the designer&#39;s aim to have as much as possible of region around the nail-hole  43  subjected to the influence of the nail. Thus, the more rigid the brick-tie in the area of the nail-hole, the more the securement provided by the nail is translated into effective restraint. 
     It may be noted that the nail is located near the angled-junction between the horizontal and vertical arms. The arms complement each other. The presence of the horizontal arm serves to stiffen the vertical arm, and prevent the vertical arm from curling or bowing, and correspondingly the presence of the vertical arm serves to stiffen the horizontal arm, and prevent the horizontal arm from curling or bowing. Again, it is noted that the stiffer the angled junction region  39  of the device, the more strongly the securement provided by the nail  27  is translated into restraint between the bricks and the studs, and the better the performance of the brick-tie in keeping constant the spacing between the bricks and the studs, under varying conditions (of weather, etc). 
     It is also noted, for the same reasons, that the stud-end  49  of the bridge  47  should be thick all the way across, i.e that the margins  50  of the stud-end  49  should be thick, as well as the centre of the stud-end. These marginal portions  50 , being thick, serve to stabilise the shape of the device at the junction, and to keep that region stiff. 
     The above remarks relating to the stud end  49  of the bridge  47  also relate to the bottom portion  52  of the vertical arm  38 , i.e the portion surrounding and below the nail-hole  43 . 
     The junction or angle area  39  of the brick-tie  26  being stiff, as described, the whole junction area remains as one. It is as if many nails had been used to secure the whole area to make it unitary with the stud. 
     The designer might indeed provide for two nails, or more. However, further nails are not preferred, because it would be more difficult then to line up both (or all) nails with the stud. This is especially the case when the bricklayer is a little too casual. Also, it would be difficult for the building inspector to tell whether both nails were properly entered into the stud. Inevitably, a significant number of brick-ties would only be attached to the stud by one nail, at one side. In the preferred arrangement, when only one nail secures the brick-tie to the stud, the bricklayer would almost have to be deliberately over-casual not to nail the brick-tie properly to the stud. 
     It may be noted that extra nails above or below the junction area would be of little use, since they would not tend to make the bridge-portion effectively unitary with the stud. 
     As mentioned, some bricklayers prefer to put the brick-ties on the wall before starting to lay the bricks, because then the nails used to secure the brick-ties can be used to secure the waterproof paper  25  to the studs also. One reason for this practice, apart from saving nails, is that builders prefer to puncture the paper in as few places as possible. The moulded brick-tie  26  as described herein can be applied in this way, but because the brick-tie  26  cannot be bent to shape, the position in which to nail the brick-tie must be pre-measured, fairly accurately, as to where the courses of bricks will lie. Of course, with care, this can be done. 
     The back-face  45  of the vertical-arm  38  of the moulded brick-tie  26  is large in area. The large area combines good securement for the paper  25 , with little chance of tearing the paper. 
     The brick-tie  26  as described herein, being of moulded plastic, can be provided with a nail-hole  43  that is slightly smaller than the nail  27 . During manufacture, nails can be inserted partway into the nail-holes in-factory, and the unit sold with the nails in place. In this regard, it may be noted that such pre-assembled nail lies within the overall outline of the device; brick-ties are generally purchased and used not individually but by the box-full, and it is important that, in the box, the nail does not protrude an awkward distance, nor at an awkward angle, with respect to the brick-tie itself 
     Also because the product is of moulded plastic, the nail-hole has length, and so can be used to position the nail at the correct angle. This may be contrasted with the conventional design, where the nail is not guided at all by the brick-tie, and can be at any angle. 
     FIGS. 6 and 7 show another version of the plastic moulded brick-tie. Here, the manner of keying the horizontal arm into the mortar is more secure, because of the profile or shape of the in-mortar portion  54  of the arm, and the holes therethrough. As shown, although ridges are not needed underneath the horizontal arm, of course they can be provided. 
     FIG. 8 shows another version of the plastic moulded brick tie. Here, the fixed structure is not a stud wall (as in FIG.  1 ), but another brick wall  56 . Again, the benefits of a thick and chunky bridge portion  57  are combined with the benefits of using plastic.