Wall Tie For Concrete Forms

Abstract

A reusable wall tie for maintaining the correct spacing between the form walls of concrete forms includes a spreader for preventing the walls from collapsing inwardly and a tie rod for preventing the walls from spreading apart. The spreader has a tapered shank and a threaded stud extending from the small end of the shank. The stud fits through a hole drilled in one of the form walls prior to the erection of the other form wall. A nut threads over the stud and temporarily secures the spreader to the form wall such that the tapered shank projects inwardly therefrom. The other form wall is positioned against the large end of the tapered shank on the spreader, and the two walls are tied together by a tie rod which extends through the spreader. After concrete is poured between the walls and allowed to set, the spreader is dislodged from the concrete by striking the stud end with a mallet.

Description

BACKGROUND OF THE INVENTION

This invention relates in general to concrete forms and more particularly to means for maintaining the proper spacing between the walls of such forms.

It is common practice in the building construction industry to pour concrete into forms constructed from large sheets of plywood which are held together by numerous steel tie rods called wall ties. These wall ties not only keep the opposed form walls from spreading, but they also prevent the walls from collapsing inwardly toward each other before concrete is poured between them. Since the wall ties are relatively thin and serve a dual purpose, numerous tie rods are employed in a single form. For example, in 100 feet of form, 8 feet high and 1 foot wide, approximately 250 wall ties are required to maintain the opposed form walls in the proper spaced relation.

After the concrete has been poured into and set within the form, a workman must go along the exterior surfaces of the form walls and clip off the exposed ends of the wall ties to free the form walls from the hardened concrete. In view of the large numbers of wall ties in conventional forms and further in view of the fact that the workman must clip both ends of each tie, the removal of forms by current procedures is a time consuming and expensive process. Moreover under present procedures, wall ties for the most part remain embedded in the concrete wall, and they therefore cannot be reused. Their ends furthermore present unsightly protrusions or blemishes along the wall.

SUMMARY OF THE INVENTION

One of the principal objects of the present invention is to provide wall ties for holding opposed walls of a concrete form in properly spaced relation. Another object is to provide a wall tie which is easy to install and is only required in relatively small members. A further object is to provide a wall tie which is easily removed from the form and from the hardened concrete in the form so that no unsightly protuberances remain in the concrete wall. An additional object is to provide a wall tie which is easily removed from the form and from the hardened concrete without damaging the wall tie so that it can be reused. Still another object is to provide a wall tie spreader which is initially embedded in the poured concrete, but is easily dislodged therefrom. These and other objects and advantages will become apparent hereinafter.

The present invention is embodied in a spreader for maintaining the proper spacing between concrete form walls. The spreader includes a tapered shank and a stud at the small end of the shank. The stud projects through one of the form walls and is engaged by attaching means which temporarily secures the spreader to that wall. The invention further resides in a wall tie including the foregoing spreader and a tie rod which extends longitudinally through the spreader and prevents the form walls from moving apart. The invention also consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed.

DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which form part of the specification and wherein like numerals refer to like parts wherever they occur:

FIG. 1 is a perspective view of a concrete form held together with wall ties constructed in accordance with and embodying the present invention;

FIG. 2 is a sectional view taken along line 2--2 of FIG. 1;

FIG. 3 is a sectional view taken along line 3--3 of FIG. 2;

FIG. 4 is a sectional view similar to FIG. 3, but showing the wall tie spreader being dislodged from the hardened concrete;

FIG. 5 is an exploded view of the wall tie spreader; and

FIG. 6 is a perspective view of a waler bracket used on the form.

DETAILED DESCRIPTION

Referring now to the drawings, 2 designates a concrete form which rests upon a footing 4 and includes a pair of spaced form walls 6 and 8 which are preferably composed of large sheets of plywood. Backing each wall 6 and 8 and also forming part of the form 2 are a plate 10 which extends along the footing 4 and a plurality of studs 12 which are set upon and extend upwardly from the plate 10 at equally spaced intervals. The studs 12 in turn are backed by horizontal walers 14 which are secured to the studs by waler brackets 16. Thus, the studs 12 and walers 14 serve as reinforcing members for the form walls 6 and 8. Each of the brackets 16 comprises (FIG. 6) two pairs of spaced flanges 18 and 20 extending from a common connecting portion 22 and presented at right angles to one another. The spacing between the flanges 18 is slightly greater than the width of the stud 12 to which the bracket 16 attaches, and this enables the flanges 18 to fit over the wall studs 12. The spacing between the flanges 20 is sufficient to enable them to receive the walers 14 to which the bracket 16 also attaches. The flanges 18 and 20 have apertures 24 through which nails are driven for securing the brackets 16 to both the studs 12 and the walers 14. Normally, the plates 10 are 2 inch .times. 4 inch timbers, the studs 12 are 4 inch .times. 4 inch timbers, and the walers 14 are 4 inch .times. 6 inch timbers.

To maintain the proper spacing between the opposed form walls 6 and 8, a multiplicity of wall ties 30 are connected between the opposed walls 6 and 8 and portions of these wall ties 30 extend through the walers 14 which back the studs 12. Thus, the wall ties 30 are disposed in horizontally extending rows at the levels at which the walers 14 are presented. Each wall tie 30 includes (FIG. 3) a spacer or spreader 32 which prevents the opposed walls 6 and 8 from collapsing inwardly toward each other, and a tie rod 34 which extends through the spreader 32 and also through the walers 14 for preventing the walls 6 and 8 and the walers 14 backing them from spreading apart.

More specifically, each spreader 32 includes (FIG. 5) a tapered shank 36 having a radially extending lip 38 at its large diameter end. The end face of the lip 38 is continuous with the end face of the spreader 32 and is squared off relative to the axis of the shank 36 so as to form an abutment 40 thereon. At its opposite or small diameter end the tapered shank 36 is also squared off in the formation of an abutment shoulder 42 from which a threaded stud 44 projects along the axis of the shank 36. The threaded stud 44 is formed integral and coaxial with the tapered shank 36 and projects through a pair of washers 46 and 48. Its threads are engaged by a nut 50.

When the spreader 32 is emplaced in the form 2 (FIG. 3), the threaded stud 44 extends through the form wall 6, and the washer 46 is positioned on one side of the wall 6 while the washer 48 is positioned on the opposite side. The nut 50 tightens down upon the washer 48 and when so tightened the washers 46 and 48 and the wall 6 are clamped between the shoulder 42 and the nut 50. This temporarily secures the spreader 32 to the wall 6 with its tapered shank 36 projecting perpendicularly from the inside face thereof.

Finally the spacer 32 has an axially extending bore 52 which extends completely through the tapered shank 36 and threaded stud 44 and is large enough in diameter to loosely receive the tie rod 34.

Each tie rod 34 is long enough to extend completely through the axially extending bore 52 of its corresponding spreader 32 as well as through the walers 14 located beyond each end of the spreader 32. At its one end the tie rod 34 is provided with an enlarged head 54, while at its opposite end it is provided with threads 56 which extend beyond the waler 14 at that end. The threads 56 are engaged by a nut 58 which tightens down against a small plate 60 located against the outer surface of the waler 14. Similarly, the head 54 bears against a plate 60 on the opposite waler 14. In lieu of the head 54, the tie rod 34 may at that end be provided with threads 54 and a nut 58 also.

To construct a concrete wall by means of the form 2, the footing 4 is first poured in the conventional manner. Once the footing 4 has set, the plate 10 for the form wall 6 is laid along the upper surface of the footing 4 adjacent to one side thereof. Next the vertical flanges 18 of the waler brackets 16 are fitted over and nailed to the studs 12 at the spacing selected for the walers 14. When the brackets 16 are correctly mounted, their common connecting portions 22 will bear against the outwardly presented surfaces of the studs 12. Then with the waler brackets 16 presented outwardly the studs 12 are raised and toenailed to the plate 10 and at least some of the studs 12 are supported in an upstanding position by suitable bracing which extends away from the footing 4. Thereafter the walers 14 are fitted between horizontal flanges 20 of the waler brackets 16 and are nailed in place to secure the walers 14 to the studs 12 at the desired vertical spacing.

Once the walers 14 are attached to the studs 12, the form wall 6, which is normally composed of several large sheets of plywood, is positioned against the inwardly presented unobstructed surfaces of the studs 12 and is nailed thereto at a few locations. Next holes 62 (FIG. 3) large enough to receive the threaded stud 44 on the spreader 30 are drilled in the form wall 6 opposite to the walers 14. To provide the same hole spacing in the form wall 8 it is desirable to place that wall temporarily against the wall 6 and drill the holes 62 through both at the same time. Thereafter holes 64 (FIG. 3) large enough to receive the tie rods 34 are drilled in the walers 14 which back the wall 6 and these holes align with the holes 62 in the wall 6.

After the wall 6 has been erected and provided with the holes 62, the threaded stud 44 of a spreader 32 is inserted through each hole 62. Of course, to accomplish this the nut 50 must be removed, but the washer 46 remains on the threaded stud 44 so that it is interposed between the abutment shoulder 42 at the end of the tapered shank 36 and the inwardly presented surface of the wall 6. Then the other washer 48 and nut 50 are fitted over the end of the stud 44 exposed on the opposite or outer side of the wall 6. In this connection, it should be noted that the length of the threaded studs 44 is somewhat less than the depth of the wall studs 12 so that adequate clearance exists between the ends of the threaded studs 44 and walers 14 for installation of the nuts 50 on the studs 44. Each nut 50 is tightened down against its respective washers 48 and this firmly, yet temporarily, positions the spreaders 32 on the wall 6 such that the tapered shanks 36 thereof project perpendicularly from the inwardly presented surface of the wall 6.

Once the spreaders 32 are emplaced the other form wall 8 is brought against the abutments 40 on the tapered shanks 36 of those spreaders 32. Since the holes 62 were drilled in both walls 6 and 8 at the same time, the abutment 40 will extend around the peripheries of the holes 62 in the wall 8 and the axial bores 52 through the spreaders 32 will align with those holes. Then the other plate 10 is laid on the upper surface of the footing 4 and more studs 12 are erected on that plate 10 in the same manner. Similarly, walers 14 are secured along the outer sides of the studs 12 by waler brackets 16, and these walers 14 are located opposite to the holes 62 in the wall 8. The walers 14 backing the wall 8 are likewise drilled to provide holes 64 which align with the holes 62 in the wall 8 and are large enough in diameter to receive the tie rods 34.

After the erection of the wall 8 and the studs 12 and walers 14 backing it, the tie rods 34 are passed through the aligned holes 64 and 62 in the walers 14 and walls 6 and 8 as well as through the axial bores 52 in the spreaders 32. The head 54 at one end of each tie rod 34 bears against the adjacent waler 16 through the plate 60 which encircles that tie rod, whereas at the opposite end of the tie rod 34 the nut 50 is engaged with the threads 56 and tightened down against the opposite plate 60 which in turn bears against the opposite waler 14.

Thus the tie rods 34 urge the opposed form walls 6 and 8 inwardly and thereby keep them from falling away from each other. The spreaders 32, on the other hand, by reason of the fact that they abut against the inwardly presented surfaces of the walls 6 and 8 at the washers 46 and the abutments 40, respectively, prevent the walls 6 and 8 from collapsing inwardly and furthermore maintain the correct spacing between the walls 6 and 8 so that those walls remain truely parallel.

After the form 2 has been erected in the foregoing manner, concrete is poured between the walls 6 and 8 and allowed to set into a hardened concrete wall 66. Removing the form 2 from the wall 66 is a simple procedure. More specifically, the form 2 is stripped away from the poured wall 66 by first removing the nuts 58 from the ends of the rods 34 and then withdrawing the tie rods 34 completely from the spreaders 32 as well as from the walls 6 and 8 and the walers 14 backing those walls. Since the tie rods 34 extend through the bores 52 in the spreaders 32, and are not embedded in the concrete, they are easily withdrawn from the poured concrete wall 66. Then the studs 12 and walers 14 are removed from both form walls 6 and 8, and the wall 8 is further stripped away leaving one surface of the poured concrete wall 66 exposed and the other surface covered by the form wall 6. Next the nuts 50 which formally held the spreaders 30 in place, are threaded outwardly until their outer end faces are presented slightly beyond the ends of the threaded studs 44, in which case the nuts 50 will still remain engaged with the studs 44. Then each nut 50 is struck with a wooden or hard rubber mallet, the blow being directed axially toward the large diameter end of the tapered shank 36 (FIG. 4). This dislodges the shank 36 from the set concrete and frees it for removal from the opposite side of the concrete wall 66 once the nut 50 and washer 46 are removed.

After the spreader 32 is removed from the concrete wall 66, the ends of the transversely extending hole left by it are plugged with a quick drying mortar such as POROX. The shallow recesses left in the wall 66 by the washer 66 and lip 38 provide a greater surface area along which the mortar adheres, and thus the ends of the holes formerly occupied by the spreader 32 are sealed, without leaving unsightly protrusions or blemishes on the wall.

Relatively few wall ties 30 are required to hold the form 2 together when compared with the number of conventional ties required to hold a form of equivalent size together. For example, in a form 100 feet long, 8 feet high, and 1 foot wide at the walls 6 and 8, 75 wall ties 30 are required, whereas 250 conventional wall ties are required for a conventional form the same size. This reduces the labor required to construct the form 2, resulting in a considerable saving to the user.

Moreover conventional wall ties remain embedded in the concrete, whereas the wall tie 30 is completely withdrawn and can therefore be used again. This reusable feature of the wall ties 30 in the long run affords a sizeable saving, notwithstanding the greater initial cost. In this same vein, the wall ties 30 are not clipped off on each side of the concrete wall 66 as are conventional ties, and this not only represents a saving in labor, but it also eliminates unsightly protuberances projecting from the wall.

The form 2 may also be constructed with the studs 12 and walers 14 reversed. In other words, the walers 14 may be placed directly against the walls 6 and 8 and backed with the studs 12. In such a construction the number of walers 14 would be increased and the number of studs 12 decreased in comparison to the previously described construction. Also the tie rods 34 would extend through the outwardly spaced studs 12 of such a construction instead of through the walers 14.

This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

Claims

What is claimed is:

1. A spreader for use in a concrete form having a pair of spaced walls which are held together by tie rods, said spreader comprising a tapered shank terminating at abutments which are positioned adjacent the opposed surfaces of the walls for preventing the walls from moving toward each other, a reduced stud extending from the shank and projecting beyond the abutment at the small end of the shank and through the wall adjacent to which that abutment is positioned, removeable attaching means engageable with the stud for temporarily securing the spreader to the wall through which the stud projects, and a bore extending through the shank and stud for accommodating the tie rod.

2. A spreader according to claim 1 wherein the tapered shank and stud are disposed about a longitudinal axis for the spreader; and wherein the greatest dimension of the stud taken normal to the longitudinal axis is less than the smallest dimension of the tapered shank taken normal to the longitudinal axis.

3. A spreader according to claim 2 wherein the tapered shank is circular in cross-section and the abutment at the small end of the shank is a shoulder.

4. A spreader according to claim 3 wherein the shank is provided with a radially projecting lip at its large end; and wherein the abutment at the large end of the shank is formed in part on the lip.

5. A spreader according to claim 3 wherein the stud is provided with external threads; and wherein the removable attaching means is a nut which engages the threads and when tightened down causes the wall through which the stud extends to be clamped between the shoulder and the nut whereby the tapered shank will project outwardly from that wall.

6. A spreader according to claim 5 wherein a washer is interposed between the shoulder and the wall through which the stud extends.