CA2170952A1 - Concrete form tie - Google Patents
Concrete form tieInfo
- Publication number
- CA2170952A1 CA2170952A1 CA 2170952 CA2170952A CA2170952A1 CA 2170952 A1 CA2170952 A1 CA 2170952A1 CA 2170952 CA2170952 CA 2170952 CA 2170952 A CA2170952 A CA 2170952A CA 2170952 A1 CA2170952 A1 CA 2170952A1
- Authority
- CA
- Canada
- Prior art keywords
- tie
- concrete form
- covering
- readily
- concrete
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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- Forms Removed On Construction Sites Or Auxiliary Members Thereof (AREA)
Abstract
An improved concrete form tie includes a readily compressible member covering at least parts of the regions of the tie that are deposed within the walls of the form when the ties are installed in the form.
Description
G~ OlOD\POOOl\SP13C3.~0C 9 March 1995 RW3!~D/jl -IMPROVED ~ON~K~l~ FORM TIE
R~GROUND OF 'L4~ lNV'-~.llON
1. Field of the Invention The present invention relates generally to form ties for concrete wallforms, and more particularly to form ties having compressible members or similar means attached thereon.
R~GROUND OF 'L4~ lNV'-~.llON
1. Field of the Invention The present invention relates generally to form ties for concrete wallforms, and more particularly to form ties having compressible members or similar means attached thereon.
2. Description of the Prior Art lS Wallform construction method~ are well known in the construction trade and widely used in construction of residential and commercial concrete foundations and ret~; n; ng walls. The present invention is for use with wallform construction in which a wall form (typically comprising spaced plywood sheets) is used to hold the fresh concrete in the desired shape until it sets.
To do this, the plywood walls of the form must be prevented from 8pre~A; ng apart from one another due to the pressure of the fresh concrete placed between them. One commonly used means to hold the walls (e.g. sheets of plywood) in the required spacing is to use form ties that pass through the space between the walls into ' .
which the fresh concrete will be placed and protrude on both sides of the form through holes in the walls. A holding means is then attached to each protruding portion of each of the form ties to prevent the walls from being pushed apart. One simple example of ~uch holding means is a holding bar (referred to in the prior art as a wailer bar) passing through a mating hole in each protruding portion of the form ties.
After the concrete is poured into the cavity in the form between the wall~ and has set (become hard enough to ~tand on its own), the holding bars (wailer bars) are removed, and the protruding portions of the form ties are ~truck with a h~mm~r or bar to break the protruding portions of the form tie~ off. The break typically occurs at a point just inside the surface of the concrete wall (the ties having been shaped 80 that they are narrower and thu~ weaker at the point at which breaking i~
desired). The form board~ are then removed, leaving no portion~
of the ties protruding from the concrete wall~.
To do this, the plywood walls of the form must be prevented from 8pre~A; ng apart from one another due to the pressure of the fresh concrete placed between them. One commonly used means to hold the walls (e.g. sheets of plywood) in the required spacing is to use form ties that pass through the space between the walls into ' .
which the fresh concrete will be placed and protrude on both sides of the form through holes in the walls. A holding means is then attached to each protruding portion of each of the form ties to prevent the walls from being pushed apart. One simple example of ~uch holding means is a holding bar (referred to in the prior art as a wailer bar) passing through a mating hole in each protruding portion of the form ties.
After the concrete is poured into the cavity in the form between the wall~ and has set (become hard enough to ~tand on its own), the holding bars (wailer bars) are removed, and the protruding portions of the form ties are ~truck with a h~mm~r or bar to break the protruding portions of the form tie~ off. The break typically occurs at a point just inside the surface of the concrete wall (the ties having been shaped 80 that they are narrower and thu~ weaker at the point at which breaking i~
desired). The form board~ are then removed, leaving no portion~
of the ties protruding from the concrete wall~.
3. Problems Encountered in the Prior Art A common problem encountered in the use of such form ties i~ the penetration of unwanted concrete into the space between the sides of the wall fonm and the side~ of the hole in the wall 2170g-52 through which the form tie passes; The holes are initially cut to a size somewhat larger than the cross-sectional dimension~ of the form tie to allow easy assembly of the ties and forms. For this reason, some wet concrete tends to leak into the spaces in the wall holes around the form ties. This leakage tends to leave small amounts of concrete rer~; n; ng in the holes in the walls after the forms are removed from the newly set concrete wall.
So that the plywood walls may be reused, the remaining concrete is cleaned out of the wall holes using an air chisel or a hammer and chisel. In doing 80, the holes tend to become enlàrged, shortening the usable life of the form boards.
A second problem with the use of such forms is that if concrete leaks around the tie into the hole in the form board, some concrete will also remain at~h~ to the concrete wall when the form board is removed, leaving a rough surface with concrete knobs that must be knocked off.
A third problem with the use of such ties is the tendency for the form tie6 to fall out of the holes as the forms, form ties, and wailer bars are being assembled (before the concrete is poured). This problem tends to be accentuated by repeated reuse of the walls as the holes for the ties become worn larger.
If form ties that fall out are not replaced, leakage of concrete ~ 2170~9S2 through the holeR in the walls from which ties are missing will occur and the lateral strength of the form where ties are missing will be reduced. Fi n~; ng and replacing form ties that have fallen out is difficult and time-consuming.
There are a wide variety of shapes of form tie~ (also known as form tie rods and form tie strapQ in the prior art) using a wide variety of holding mechanismR. Some of these systems deal with the concrete leakage problem, but in ways that are complicated and expenRive when compared to the preRent invention.
Examples of flat form ties or straps that dd not include sealing means to reduce concrete leakage include those disclosed in SummerR, U.S. Patent No. 1,920,607, Schwaab, U.S. Patent No.
1,978,963, Clark, U.S. Patent No. 2,887,758, Bowden, U.S. Patent No. 3,362,678, Ward et al., U.S. Patent No. 3,995,825, and Sawyer, U.S. Patent No. 4,239,173. Examples of flat form ties or straps that do include sealing means such as cones or plugs to reduce concrete leakage include thone disclosed in Imonetti, U.S. Patent No. 2,948,045, Brosseau, U.S. Patent No. 3,643,909, Shoemaker, U.S. Patent No. 3,653,628, and Taraldsson, U.S. Patent No. 5,282,603. An example of a rod type form tie that does not include sealing means to reduce concrete leAkA~e is disclosed in Daniels, Jr., U.S. Patent No. 3,746,297. Examples of rod type form ties that do include seAl;ng means such as cones, blR~;ngs, (-` 217~g52 or plugs to reduce concrete leakage include those disclosed in Franklin, U.S. Patent No. 3,612,473, Eriksson, U.S. Patent No.
3,618,887, Beaker, U.S. Patent No. 3,880,397, and Holmboe, U.S.
Patent No. 4,054,258.
Ties provided with cones, bushings or plugs tend to be difficult to insert within the form wall holes. Further, because they lack resilience, they cannot be readily deformed to conform to the shape and size of a roughly-opened hole (typical of plywood form walls).
So that the plywood walls may be reused, the remaining concrete is cleaned out of the wall holes using an air chisel or a hammer and chisel. In doing 80, the holes tend to become enlàrged, shortening the usable life of the form boards.
A second problem with the use of such forms is that if concrete leaks around the tie into the hole in the form board, some concrete will also remain at~h~ to the concrete wall when the form board is removed, leaving a rough surface with concrete knobs that must be knocked off.
A third problem with the use of such ties is the tendency for the form tie6 to fall out of the holes as the forms, form ties, and wailer bars are being assembled (before the concrete is poured). This problem tends to be accentuated by repeated reuse of the walls as the holes for the ties become worn larger.
If form ties that fall out are not replaced, leakage of concrete ~ 2170~9S2 through the holeR in the walls from which ties are missing will occur and the lateral strength of the form where ties are missing will be reduced. Fi n~; ng and replacing form ties that have fallen out is difficult and time-consuming.
There are a wide variety of shapes of form tie~ (also known as form tie rods and form tie strapQ in the prior art) using a wide variety of holding mechanismR. Some of these systems deal with the concrete leakage problem, but in ways that are complicated and expenRive when compared to the preRent invention.
Examples of flat form ties or straps that dd not include sealing means to reduce concrete leakage include those disclosed in SummerR, U.S. Patent No. 1,920,607, Schwaab, U.S. Patent No.
1,978,963, Clark, U.S. Patent No. 2,887,758, Bowden, U.S. Patent No. 3,362,678, Ward et al., U.S. Patent No. 3,995,825, and Sawyer, U.S. Patent No. 4,239,173. Examples of flat form ties or straps that do include sealing means such as cones or plugs to reduce concrete leakage include thone disclosed in Imonetti, U.S. Patent No. 2,948,045, Brosseau, U.S. Patent No. 3,643,909, Shoemaker, U.S. Patent No. 3,653,628, and Taraldsson, U.S. Patent No. 5,282,603. An example of a rod type form tie that does not include sealing means to reduce concrete leAkA~e is disclosed in Daniels, Jr., U.S. Patent No. 3,746,297. Examples of rod type form ties that do include seAl;ng means such as cones, blR~;ngs, (-` 217~g52 or plugs to reduce concrete leakage include those disclosed in Franklin, U.S. Patent No. 3,612,473, Eriksson, U.S. Patent No.
3,618,887, Beaker, U.S. Patent No. 3,880,397, and Holmboe, U.S.
Patent No. 4,054,258.
Ties provided with cones, bushings or plugs tend to be difficult to insert within the form wall holes. Further, because they lack resilience, they cannot be readily deformed to conform to the shape and size of a roughly-opened hole (typical of plywood form walls).
4. Summary of the Invention The present invention is an improved form tie including means for inhibiting the ties from falling out of the walls and for reducing concrete leakage, that has the advantages of low - cost and simplicity as compared to previously known ties.
The present invention comprises a ~ollvelltional flat form tie of the type common in the prior art with an added readily compressible covering member (e.g. a pad or pads of open cell polyfoam stripping commonly used as weather stripping) covering at least parts of the two region~ of the tie that fit in the holes in the form wall~. me member may be, for example, a foam pad adhered to at least one flat side and preferably both flat 2170~52 sides of the tie in the vicinity of each of the aforesaid two regions (hereinafter "wall regions~, signifying that such regions are disposed within the walls of the form when the ties are installed in the form). It has been found that this use of a compressible pad or the like solves the problems in the prior art referred to above by (i) creating a friction fit of the tie with the adhered pad (say) within the hole in the form wall, thereby inhibiting the tie from falling out of the hole before the concrete iæ poured; and (ii) filling moæt of the æpace between the form tie and the form board, thereby inhibiting concrete from leaking into the form board holeæ and thence out of the form.~
The holes tend to be kept relatively clean allowing easy reuse of the form boards. The concrete wall tends to be clean also, without protruding concrete knobs, and the tie tends to be held ~ tely in place while the waIls are being subjected to shock;
as when hammering occursi e.g. when the holding (wailer) bars for other ties are being hammered~into place. - ~
Note that the ready deformability of the pads permits the combined cross-sectional shape and-size of the tie bearing the pad to fill mo~t of the a~ociated wall hole (whoGe ~;m~n~ions and shape are not usually finely controlled). Further, ~uch deformability permits the tie with its pad to penetrate into the wall form hole easily. A rest shape and size of cross-section ~ 2170952 of the tie and pad (without deformity of the pad) that in roughly that of the wall hole to be filled, or slightly larger than the wall hole to be filled (BO that the pad deforms to accommodate itself to the available space within the hole) is preferred.
Several variants of the present invention are possible.
Variants (sometimes referred to hereinafter generally as "pads") include (1) those that completely cover the wall region of the form tie (including both the flat surfaces as well as the edges), such as (a) a collar, (b) a wrap-around strip that doubles back to cont~ct itself, or (c) a pair of opposed pad constituents that stick together beyond the edges of the flat surface of the form tie, as well as (2) those that cover one or both flat surfaces of the form tie such as strips.
Variants of the pre~ent invention can also be applied to form ties known in the industry as blind ties. Blind ties are used when a wall is being cast against an existing ntructure.
In that situation only one end of the form tie needs a deformable covering, the other end being replaced by a means for anchoring the form tie to the existing structure.
21709~ -BRIFF DESCRIPTION OF T~E DRAWINGS
Figure 1 is an elevation view of a form tie installed in a portion of a concrete form, as known in the prior art.
Figure 2 is an elevation view of a portion of a concrete form with an array of installed form ties and wailer bar~, a~ -known in the prior art.
Figure 3 is a plan view of a portion of a concrete form with installed form ties and wailer bars, as known in the prior art.
Figure 4 is a elevation view of an emhoA;~ent of a form tie according to the invention.
Figure 5 is a cross-sectional end view of the form tie of Figure 4.
Figure 6 is a cross-sectional end view of another embodiment of form tie according to the invention.
Figure 7 is a cro~s-sectional end view of a further embodiment of form tie according to the invention.
~ 2170952 Figure 8 is a cross-sectional end -view of a further embodiment of form tie according to the invention.
Figure 9 i8 an isometric partial view of the form tie of Figure 4 shown installed in a concrete form wall.
Figure 10 is a plan view of a joined set of form tieæ each conforming to Figure 4, shown as manufactured and ready for use.
DFT~TT-Tm DESCRIPTION OF THE INVgNTION
The preferred embodiment of the invention comprises an improvement of a conventional form tie. Form ties as known and used heretofore are described first, and then the improvement of the present invention will be described.
Figures 1, 2, and 3 illustrate a typical conventional form tie and its use. A typical form tie 10, illustrated in Figure 1, is made of approximately 16 gauge good quality steel 3/4"
wide. Its length is determined by the spacing between the form walls. The tie 10 has a ~lot 14 pllnche~ or cut near each end to allow a flat steel wailer bar 22 (see Figures 2 and 3), typically 3/4" x 1/4 n in section, to slide through the slots li, thereby to provide lateral strength for the form, and to keep the ties ~ 2170952 in position. This type of -tie i~ made in various lengths depending on the desired thickness of the concrete wall.
The ties 10 are inserted through oblong holes or slots 20 in the concrete form walls 12. The wall~ 12 are typically plywood panels of 3/4 n thickness. The slots 20 are often cut using a plunge router (resulting in semi-circular slot ends) with a 3/16" bit and typically are approximately 1 1/4" to 1 1/2 n long. The long dimension of each slot 20 is typically somewhat greater than the width of the form tie 10 to allow for ease of insertion of the tie 10 into the slot 20. The form ties are weakened, in this example by cutting notches 16, at the point~
at which it is desired that the form tie~ be broken off after the concrete has set. Other designs (for example, Ward et al., U.S.
Patent No. 3,995,825) are known that include other means to weaken the form tie at the desired location. After the forms are placed in the required locations and wailer bars 22 are inserted through the holes 14 in the form ties, wet concrete is poured into the space 18 between the forms 12.
When the concrete has set (become firm enough to stand on its own~, the wailer bars 22 are removed and the ends of the form ties 10 are broken off at the weakened points 16 by striking them with a heavy hammer or bar. The forms 12 are then removed and . .
~ 2170~5Z
.the holes 20 cleaned out for reuse. ChiQels or other tools are needed to remove any concrete sticking to the forms 12.
The present invention compri6es the above-described form tie 10 with the addition of a readily compressible covering ~uch as a pair of pads 30 attached as shown, for example, in Figures 4 to 10. (The term "pad" herein i~ intended to apply to any relatively flat material that can be readily compre~sed and deformed, includes ~uch material in more than one piece, and include~ such material wrapped or bent to conform to the ~urfaces of the metal tie.) Each of the compressible coverings 30 is attarhe~ to the same region (the "wall region") of the form tie 10 that is within the hole or slot 20 in the form wall 12 at the time the concrete is poured into the ~pace 18 between the walls 12. The compressible covering 30 fill~ most of the space between the Rides of the aQsociated hole 20 in the form wall 12 and the metal portion of the form tie 10, t~n~; ng to inhibit leakage of the concrete out of the form, and reducing both (1) the need to clean the forms 12 after use; and (2) the need to knock concrete protru~ions (knob~) off the newly formed concrete wall.
Because the covering 30 iB readily compre~ible and deformable, it~ thickness can vary from a maximum rest dimension to a minimum dimen~ion that i~-~carcely greater than zero. For - 21709~2 this reason, the form tie 10 with the compressible covering 30 tends to fit snugly within the slot or hole 20, even if the hole 20 is somewhat enlarged. This capability of the compressible covering to contract readily from its maximum dimension enables the tie 10 to be inserted easily into the slot 20 even though the combined rest thickness of the covering 30 and tie 10 should preferably slightly exceed the width of the slot 20. Designing the pad 30 to be somewhat oversize relative to the hole dimensions facilitatee a snug fit within the hole 20.
Nevertheless, the ready deformability of pad 30 implies that the presence of pad 30 on the tie 10 does not seriously interfere with the penetration of the tie 10 into the hole 20. This characteristic re~llce~ the possibility of the form tie 10 falling out of the form wall 12 during assembly of the forms.
Figure 5 illustrates the form tie 10 of Figure 4 in cross-section. In this embodiment, which is a preferred embodiment, the compressible covering 30 extends beyond the side edges of the form tie 10, which has es~entially identical obverse and reverse flat surfaces 31, 33. The protruding ends 32 of the coverings 30 meet along contiguous faces 34. If the covering~ 30 have a&esive faces 34, there will ~e little t~n~ncy of the covering~
30 to slip off the ties 10. The opposed adhesive faces 34 tend to adhere strongly to one another and less strongly to the ,` 217~52 ~~ obverse and reverse flat surfaces 31, 33 of the tie 10. Cle~n; ng the flat surfaces 31 and 33 would improve adhesion of the pads 30, but may not be economically justifiable.
Note that the pad 30 of Figure 5, shown formed by two adhered pieces of adhesive polyfoam strip 35, 37, could instead by formed by one single strip ~.ld~ed around the tie 10 and whose ends overlap and join together adhesively. An alternative embodiment to that illustrated in Figure S could also be fabricated as a one-piece collar that could be slid onto the form tie 10 or formed in place of the form tie 10.
Figure 6 illustrates a variant of the present invention in which the compressible covering 30 is attached to only one side of the form tie 10 and extends beyond the edges of the form tie 10. Figure 7 illustrates another variant of the tie of the present invention in which the compressible covering 30 is attached to only one side of the form tie 10 and does not extend beyond the edges of the form tie 10. Figure 8 illustrates another variant of the tie of the invention with the compressible covering attached to both sides of the form tie 10 but not ext~n~; ng beyond the edges of the form tie 10.
Figure 9 illu~trateQ the u~e of the tie 10 of Figure 4 in 2170~52 a form wall 12, depicted in isometric view. Note that there may be a space or spaces 16 around or at the side edges of the form tie 10 not filled by the compressible covering 30. Experience has shown that a small space such as spaces 16 shown is not seriously detrimental to the successful functioning of the improved form tie according to the invention.
The preferred embodiment of the pad 30 (illustrated in cross-section in Figure 5 and in the left exemplification of Figure 4) can be manufactured by applying commercially available open cell polyester foam weather stripping having measurements of 3/4" or preferably at least 1/2" wide by 3/16" thick to conventional commercially available 8/4 n wide 16 or 17 gauge steel form ties 10 in lengths ~ep~n~nt on the desired thickness of the concrete wall. Weather etripping 40 is commonly available with one side covered with adhesive (as purchased, this side is typically temporarily covered in turn with a removable paper release strip). To apply weather stripping to the form tie6 10, two strips 40 of weather stripping (Figure 10) laid sticky side up at the proper sp~c;ng from one another, as determined from the desired form ~p~c;ng, and the release layer is L~ ved. The form ties lo are then in a suitable 8p~C~ array (say placed 1" apart) on the sticky side of the weather stripping 40, so that the wall regions 18 of the ties 10 (see Figure 4) are respectively aligned 2170~52 with associated ones of the two strips 40 of weatherstripping.
Two further ~trips of weather ~tripping 40 are then aligned with the ~ticky-~ide-up strips 40 and are placed sticky side down over the form ties 10, so that the stick-~ide-up ~trips 40 contact and 5 adhere to the sticky-side-down strips 40 in regions 44 between the ties 10. The weather stripping i~ perforated along lines of weakening 42 to allow the form tie~ 10 to be carried by a worker in large quantities into the field, yet ea~ily detached from one another for ready instAllAt;on. (Alternatively, weatherstripping 10 the could be severed along lines 42 and the separated ties 10 packaged and/or carried individually.) Dep~n~l;ng upon available ~izes of polyfoam strip, the pad 30 could be ~omewhat narrower or wider than the width of the form wall 12 with which the tie 10 is to be used.
One advantage of the preferred e~oA;ment of Figure 5 over the other variants of the pre~3ent invention illu~3trated in Figures 6, 7, and 8 ie enhAnced integrity of the compressible covering and the increa~ed degree of attachment to the ~teel form 20 tie resulting from tlep~n~l~nce not only on adhesion to the steel form tie, but al~o on a&e~ion between the two strips of weather~tripping. This i~ a particular advantage if form tie~
with an oily anti-ru~t coating are used (which can prevent or inhibit firm a&esion of the pad 30 to the flat surface(~) of the tie 10). The coating can interfere with the adhesion of the weatherstripping to the form tie, possibly allowing the compressible covering to become detached from the steel tie during assembly of the concrete forms. To further circumvent this problem, some slight stretching of the polyfoam material during the manufacturing operation could be effected, tending to form a pad around the metal tie that is slightly under tension, gripping the metal tie snugly.
A second advantage of the preferred embodiment of Figure 5 (also shared by the variant illu~trated in Figure 6) is a result of ext~n~ the compressible covering over the edges of the form ties thereby at least partially filling the rounded portion of the hole 20 in the form wall 12 caused by the use of a router to cut the hole 20. By having portions of the compressible cover 30 extend both above and below the edges of the form tie (as protruding portions 38, 39 in Figure 6, for example), the region of the form wall 12 around the hole 20 is somewhat cushioned from impact by the e~t~n~;ng portions 38, 39 of pad 30 adhered to form tie 10 as the form tie 10 i8 struck by hammer or similar tool during the process of breaking the form tie to allow removal of the form.
The present invention comprises a ~ollvelltional flat form tie of the type common in the prior art with an added readily compressible covering member (e.g. a pad or pads of open cell polyfoam stripping commonly used as weather stripping) covering at least parts of the two region~ of the tie that fit in the holes in the form wall~. me member may be, for example, a foam pad adhered to at least one flat side and preferably both flat 2170~52 sides of the tie in the vicinity of each of the aforesaid two regions (hereinafter "wall regions~, signifying that such regions are disposed within the walls of the form when the ties are installed in the form). It has been found that this use of a compressible pad or the like solves the problems in the prior art referred to above by (i) creating a friction fit of the tie with the adhered pad (say) within the hole in the form wall, thereby inhibiting the tie from falling out of the hole before the concrete iæ poured; and (ii) filling moæt of the æpace between the form tie and the form board, thereby inhibiting concrete from leaking into the form board holeæ and thence out of the form.~
The holes tend to be kept relatively clean allowing easy reuse of the form boards. The concrete wall tends to be clean also, without protruding concrete knobs, and the tie tends to be held ~ tely in place while the waIls are being subjected to shock;
as when hammering occursi e.g. when the holding (wailer) bars for other ties are being hammered~into place. - ~
Note that the ready deformability of the pads permits the combined cross-sectional shape and-size of the tie bearing the pad to fill mo~t of the a~ociated wall hole (whoGe ~;m~n~ions and shape are not usually finely controlled). Further, ~uch deformability permits the tie with its pad to penetrate into the wall form hole easily. A rest shape and size of cross-section ~ 2170952 of the tie and pad (without deformity of the pad) that in roughly that of the wall hole to be filled, or slightly larger than the wall hole to be filled (BO that the pad deforms to accommodate itself to the available space within the hole) is preferred.
Several variants of the present invention are possible.
Variants (sometimes referred to hereinafter generally as "pads") include (1) those that completely cover the wall region of the form tie (including both the flat surfaces as well as the edges), such as (a) a collar, (b) a wrap-around strip that doubles back to cont~ct itself, or (c) a pair of opposed pad constituents that stick together beyond the edges of the flat surface of the form tie, as well as (2) those that cover one or both flat surfaces of the form tie such as strips.
Variants of the pre~ent invention can also be applied to form ties known in the industry as blind ties. Blind ties are used when a wall is being cast against an existing ntructure.
In that situation only one end of the form tie needs a deformable covering, the other end being replaced by a means for anchoring the form tie to the existing structure.
21709~ -BRIFF DESCRIPTION OF T~E DRAWINGS
Figure 1 is an elevation view of a form tie installed in a portion of a concrete form, as known in the prior art.
Figure 2 is an elevation view of a portion of a concrete form with an array of installed form ties and wailer bar~, a~ -known in the prior art.
Figure 3 is a plan view of a portion of a concrete form with installed form ties and wailer bars, as known in the prior art.
Figure 4 is a elevation view of an emhoA;~ent of a form tie according to the invention.
Figure 5 is a cross-sectional end view of the form tie of Figure 4.
Figure 6 is a cross-sectional end view of another embodiment of form tie according to the invention.
Figure 7 is a cro~s-sectional end view of a further embodiment of form tie according to the invention.
~ 2170952 Figure 8 is a cross-sectional end -view of a further embodiment of form tie according to the invention.
Figure 9 i8 an isometric partial view of the form tie of Figure 4 shown installed in a concrete form wall.
Figure 10 is a plan view of a joined set of form tieæ each conforming to Figure 4, shown as manufactured and ready for use.
DFT~TT-Tm DESCRIPTION OF THE INVgNTION
The preferred embodiment of the invention comprises an improvement of a conventional form tie. Form ties as known and used heretofore are described first, and then the improvement of the present invention will be described.
Figures 1, 2, and 3 illustrate a typical conventional form tie and its use. A typical form tie 10, illustrated in Figure 1, is made of approximately 16 gauge good quality steel 3/4"
wide. Its length is determined by the spacing between the form walls. The tie 10 has a ~lot 14 pllnche~ or cut near each end to allow a flat steel wailer bar 22 (see Figures 2 and 3), typically 3/4" x 1/4 n in section, to slide through the slots li, thereby to provide lateral strength for the form, and to keep the ties ~ 2170952 in position. This type of -tie i~ made in various lengths depending on the desired thickness of the concrete wall.
The ties 10 are inserted through oblong holes or slots 20 in the concrete form walls 12. The wall~ 12 are typically plywood panels of 3/4 n thickness. The slots 20 are often cut using a plunge router (resulting in semi-circular slot ends) with a 3/16" bit and typically are approximately 1 1/4" to 1 1/2 n long. The long dimension of each slot 20 is typically somewhat greater than the width of the form tie 10 to allow for ease of insertion of the tie 10 into the slot 20. The form ties are weakened, in this example by cutting notches 16, at the point~
at which it is desired that the form tie~ be broken off after the concrete has set. Other designs (for example, Ward et al., U.S.
Patent No. 3,995,825) are known that include other means to weaken the form tie at the desired location. After the forms are placed in the required locations and wailer bars 22 are inserted through the holes 14 in the form ties, wet concrete is poured into the space 18 between the forms 12.
When the concrete has set (become firm enough to stand on its own~, the wailer bars 22 are removed and the ends of the form ties 10 are broken off at the weakened points 16 by striking them with a heavy hammer or bar. The forms 12 are then removed and . .
~ 2170~5Z
.the holes 20 cleaned out for reuse. ChiQels or other tools are needed to remove any concrete sticking to the forms 12.
The present invention compri6es the above-described form tie 10 with the addition of a readily compressible covering ~uch as a pair of pads 30 attached as shown, for example, in Figures 4 to 10. (The term "pad" herein i~ intended to apply to any relatively flat material that can be readily compre~sed and deformed, includes ~uch material in more than one piece, and include~ such material wrapped or bent to conform to the ~urfaces of the metal tie.) Each of the compressible coverings 30 is attarhe~ to the same region (the "wall region") of the form tie 10 that is within the hole or slot 20 in the form wall 12 at the time the concrete is poured into the ~pace 18 between the walls 12. The compressible covering 30 fill~ most of the space between the Rides of the aQsociated hole 20 in the form wall 12 and the metal portion of the form tie 10, t~n~; ng to inhibit leakage of the concrete out of the form, and reducing both (1) the need to clean the forms 12 after use; and (2) the need to knock concrete protru~ions (knob~) off the newly formed concrete wall.
Because the covering 30 iB readily compre~ible and deformable, it~ thickness can vary from a maximum rest dimension to a minimum dimen~ion that i~-~carcely greater than zero. For - 21709~2 this reason, the form tie 10 with the compressible covering 30 tends to fit snugly within the slot or hole 20, even if the hole 20 is somewhat enlarged. This capability of the compressible covering to contract readily from its maximum dimension enables the tie 10 to be inserted easily into the slot 20 even though the combined rest thickness of the covering 30 and tie 10 should preferably slightly exceed the width of the slot 20. Designing the pad 30 to be somewhat oversize relative to the hole dimensions facilitatee a snug fit within the hole 20.
Nevertheless, the ready deformability of pad 30 implies that the presence of pad 30 on the tie 10 does not seriously interfere with the penetration of the tie 10 into the hole 20. This characteristic re~llce~ the possibility of the form tie 10 falling out of the form wall 12 during assembly of the forms.
Figure 5 illustrates the form tie 10 of Figure 4 in cross-section. In this embodiment, which is a preferred embodiment, the compressible covering 30 extends beyond the side edges of the form tie 10, which has es~entially identical obverse and reverse flat surfaces 31, 33. The protruding ends 32 of the coverings 30 meet along contiguous faces 34. If the covering~ 30 have a&esive faces 34, there will ~e little t~n~ncy of the covering~
30 to slip off the ties 10. The opposed adhesive faces 34 tend to adhere strongly to one another and less strongly to the ,` 217~52 ~~ obverse and reverse flat surfaces 31, 33 of the tie 10. Cle~n; ng the flat surfaces 31 and 33 would improve adhesion of the pads 30, but may not be economically justifiable.
Note that the pad 30 of Figure 5, shown formed by two adhered pieces of adhesive polyfoam strip 35, 37, could instead by formed by one single strip ~.ld~ed around the tie 10 and whose ends overlap and join together adhesively. An alternative embodiment to that illustrated in Figure S could also be fabricated as a one-piece collar that could be slid onto the form tie 10 or formed in place of the form tie 10.
Figure 6 illustrates a variant of the present invention in which the compressible covering 30 is attached to only one side of the form tie 10 and extends beyond the edges of the form tie 10. Figure 7 illustrates another variant of the tie of the present invention in which the compressible covering 30 is attached to only one side of the form tie 10 and does not extend beyond the edges of the form tie 10. Figure 8 illustrates another variant of the tie of the invention with the compressible covering attached to both sides of the form tie 10 but not ext~n~; ng beyond the edges of the form tie 10.
Figure 9 illu~trateQ the u~e of the tie 10 of Figure 4 in 2170~52 a form wall 12, depicted in isometric view. Note that there may be a space or spaces 16 around or at the side edges of the form tie 10 not filled by the compressible covering 30. Experience has shown that a small space such as spaces 16 shown is not seriously detrimental to the successful functioning of the improved form tie according to the invention.
The preferred embodiment of the pad 30 (illustrated in cross-section in Figure 5 and in the left exemplification of Figure 4) can be manufactured by applying commercially available open cell polyester foam weather stripping having measurements of 3/4" or preferably at least 1/2" wide by 3/16" thick to conventional commercially available 8/4 n wide 16 or 17 gauge steel form ties 10 in lengths ~ep~n~nt on the desired thickness of the concrete wall. Weather etripping 40 is commonly available with one side covered with adhesive (as purchased, this side is typically temporarily covered in turn with a removable paper release strip). To apply weather stripping to the form tie6 10, two strips 40 of weather stripping (Figure 10) laid sticky side up at the proper sp~c;ng from one another, as determined from the desired form ~p~c;ng, and the release layer is L~ ved. The form ties lo are then in a suitable 8p~C~ array (say placed 1" apart) on the sticky side of the weather stripping 40, so that the wall regions 18 of the ties 10 (see Figure 4) are respectively aligned 2170~52 with associated ones of the two strips 40 of weatherstripping.
Two further ~trips of weather ~tripping 40 are then aligned with the ~ticky-~ide-up strips 40 and are placed sticky side down over the form ties 10, so that the stick-~ide-up ~trips 40 contact and 5 adhere to the sticky-side-down strips 40 in regions 44 between the ties 10. The weather stripping i~ perforated along lines of weakening 42 to allow the form tie~ 10 to be carried by a worker in large quantities into the field, yet ea~ily detached from one another for ready instAllAt;on. (Alternatively, weatherstripping 10 the could be severed along lines 42 and the separated ties 10 packaged and/or carried individually.) Dep~n~l;ng upon available ~izes of polyfoam strip, the pad 30 could be ~omewhat narrower or wider than the width of the form wall 12 with which the tie 10 is to be used.
One advantage of the preferred e~oA;ment of Figure 5 over the other variants of the pre~3ent invention illu~3trated in Figures 6, 7, and 8 ie enhAnced integrity of the compressible covering and the increa~ed degree of attachment to the ~teel form 20 tie resulting from tlep~n~l~nce not only on adhesion to the steel form tie, but al~o on a&e~ion between the two strips of weather~tripping. This i~ a particular advantage if form tie~
with an oily anti-ru~t coating are used (which can prevent or inhibit firm a&esion of the pad 30 to the flat surface(~) of the tie 10). The coating can interfere with the adhesion of the weatherstripping to the form tie, possibly allowing the compressible covering to become detached from the steel tie during assembly of the concrete forms. To further circumvent this problem, some slight stretching of the polyfoam material during the manufacturing operation could be effected, tending to form a pad around the metal tie that is slightly under tension, gripping the metal tie snugly.
A second advantage of the preferred embodiment of Figure 5 (also shared by the variant illu~trated in Figure 6) is a result of ext~n~ the compressible covering over the edges of the form ties thereby at least partially filling the rounded portion of the hole 20 in the form wall 12 caused by the use of a router to cut the hole 20. By having portions of the compressible cover 30 extend both above and below the edges of the form tie (as protruding portions 38, 39 in Figure 6, for example), the region of the form wall 12 around the hole 20 is somewhat cushioned from impact by the e~t~n~;ng portions 38, 39 of pad 30 adhered to form tie 10 as the form tie 10 i8 struck by hammer or similar tool during the process of breaking the form tie to allow removal of the form.
Claims (32)
1. A concrete form tie of the type used to hold form panels in position so as to define a cavity in a form for pouring a concrete wall, said tie when installed in position extending across such cavity and extending through holes or slots in the walls of the form panels, and said tie having a readily compressible covering for a substantial portion of the surface of the form tie lying within holes in the form panel walls when the form tie is installed in position in the form.
2. A concrete form tie as defined in claim 1, wherein the tie is of the type formed out of an elongated flat bar having obverse and reverse flat surfaces.
3. A concrete form tie as defined in claim 2, wherein the readily compressible covering covers selected portions of at least one of said flat surfaces of the tie.
4. A concrete form tie as defined in claim 2, wherein the readily compressible covering protrudes substantially beyond the edges of the flat surfaces of the tie.
5. A concrete form tie as defined in claim 2, wherein the covering comprises at least two spaced pads of readily deformable material, each pad lying substantially within an associated one of the holes of the form walls when the form tie is installed in position in the form.
6. A concrete form tie as defined in claim 5, wherein each said pad substantially surrounds the tie.
7. A concrete form tie as defined in claim 6, wherein each said pad is formed of two opposed strips having adhesive surfaces adhering the strips to one another at the ends thereof and adhering the strips to the flat surfaces of the tie intermediate the ends of the strips.
8. A concrete form tie as defined in claim 3, wherein the readily compressible covering protrudes substantially beyond the edges of the flat surfaces of the tie.
9. A concrete form tie as defined in claim 5, wherein each said pad is formed as two facing strips together covering a region of both flat surfaces of the tie, each said strip having adhesive material extending over the surface thereof facing the other of the strips.
10. A concrete form tie as defined in claim 3, wherein the readily compressible covering is formed from a strip of readily deformable material having adhesive material extending over the surface thereof contacting one of said flat surfaces of the tie.
11. A concrete form tie as defined in claim 4, wherein the readily compressible covering is formed from two facing strips of readily deformable material each having adhesive material extending over the surface thereof facing the other of the said strips.
12. A concrete form tie as defined in claim 8, wherein the readily compressible covering is formed as a strip of readily deformable material having adhesive material extending over the surface thereof contacting the flat surface of the tie.
13. A concrete form tie as defined in claim 9, wherein the readily compressible covering is made of polyfoam.
14. A concrete form tie as defined in claim 10, wherein the readily compressible covering is made of polyfoam.
15. A concrete form tie as defined in claim 11, wherein the readily compressible covering is made of polyfoam.
16. A concrete form tie as defined in claim 12, wherein the readily compressible covering is made of polyfoam.
17. A concrete form tie as defined in claim 1, wherein the rest cross-section area of the tie and the compressible covering is approximately equal to or slightly greater than the cross-sectional area of the hole in the form into which the tie is inserted when installed in position, thereby to inhibit removal of the tie from the form wall and to inhibit flow of concrete through the hole whilst permitting ready insertion of the tie and covering into and through the hole.
18. A concrete form tie as defined in claim 17, wherein the tie is of the type formed out of an elongated flat bar having obverse and reverse flat surfaces.
19. A concrete form tie as defined in claim 18, wherein the readily compressible covering covers selected portions of at least one of said flat surfaces of the tie.
20. A concrete form tie as defined in claim 18, wherein the readily compressible covering protrudes substantially beyond the edges of the flat surfaces of the tie.
21. A concrete form tie as defined in claim 18, wherein the covering comprises at least two spaced pads of readily deformable material, each pad lying substantially within an associated one of the holes of the form walls when the form tie is installed in position in the form.
22. A concrete form tie as defined in claim 21, wherein each said pad substantially surrounds the tie.
23. A concrete form tie as defined in claim 22, wherein each said pad is formed of two opposed strips having adhesive surfaces adhering the strips to one another at the ends thereof and adhering the strips to the flat surfaces of the tie intermediate the ends of the strips.
24. A concrete form tie as defined in claim 19, wherein the readily compressible covering protrudes substantially beyond the edges of the flat surfaces of the tie.
25. A concrete form tie as defined in claim 21, wherein each said pad is formed as two facing strips together covering a region of both flat surfaces of the tie, each said strip having adhesive material extending over the surface thereof facing the other of the strips.
26. A concrete form tie as defined in claim 19, wherein the readily compressible covering is formed from a strip of readily deformable material having adhesive material extending over the surface thereof contacting one of said flat surfaces of the tie.
27. A concrete form tie as defined in claim 20, wherein the readily compressible covering is formed from two facing strips of readily deformable material each having adhesive material extending over the surface thereof facing the other of the said strips.
28. A concrete form tie as defined in claim 24, wherein the readily compressible covering is formed as a strip of readily deformable material having adhesive material extending over the surface thereof contacting the flat surface of the tie.
29. A concrete form tie as defined in claim 25, wherein the readily compressible covering is made of polyfoam.
30. A concrete form tie as defined in claim 26, wherein the readily compressible covering is made of polyfoam.
31. A concrete form tie as defined in claim 27, wherein the readily compressible covering is made of polyfoam.
32. A concrete form tie as defined in claim 28, wherein the readily compressible covering is made of polyfoam.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US40562995A | 1995-03-16 | 1995-03-16 | |
| US08/405,629 | 1995-03-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2170952A1 true CA2170952A1 (en) | 1996-09-17 |
Family
ID=23604508
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2170952 Abandoned CA2170952A1 (en) | 1995-03-16 | 1996-03-04 | Concrete form tie |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2170952A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL2011700C2 (en) * | 2012-12-21 | 2014-06-24 | J W Fransen Beheer B V | IMPROVED SYSTEM FOR A MASON PROFILE. |
-
1996
- 1996-03-04 CA CA 2170952 patent/CA2170952A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL2011700C2 (en) * | 2012-12-21 | 2014-06-24 | J W Fransen Beheer B V | IMPROVED SYSTEM FOR A MASON PROFILE. |
| WO2014098585A1 (en) * | 2012-12-21 | 2014-06-26 | J.W. Fransen Beheer B.V. | Improved adjusting system for a masonry guide |
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