US2871542A

US2871542A - Set-back concrete-form tie with re-usable anchor pieces

Info

Publication number: US2871542A
Application number: US442681A
Authority: US
Inventors: Bergdal Ed
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-07-12
Filing date: 1954-07-12
Publication date: 1959-02-03
Anticipated expiration: 1976-02-03

Description

Feb. 3, 1959 E.KBEIRGDAL SET-BACK CONCRETE-FORM TIE WI'III RE-USABLE ANCHOR P IECES Filed July 12, 1954 United States Patent SET-BACK CONCRETE-FORM TIE WITH RE-USABLE ANCHOR PIECES Ed Bergdal, Ellensburg, Wash.

Application July 12,1954, Serial No. 442,681

6 Claims. ('Cl; 2,5-131) The'invention pertains to concrete-form ties of the type in'which a primary tie member completely embedded in the concrete is joined an inch or so within the face of the concrete to re-usable end members7 leaving the tie material within the concrete set back a predetermined desired distance from the face of the concrete when the end members, or anchors, are removed. The recesses left in the concrete upon the withdrawal of the anchors may be filled with cement mortar, thereby achieving a smooth nish, and one which is free from rust stains produced by tie-ends at the surface, thus conforming to specifications for exposed concrete surfaces requiring a blemish-free iinish.

ItA appears that the at-all practical ties of this nature heretofore used are those in which a screw connection of one type Ior another is used to join the separate members; these are expensive to manufacture, time-consuming to use, and tend to leave excessively deep recesses. these-reasons ties of this type are not generally used where they can be dispensed with. Ties of'simpler construction are commonly used whereI the circumstances permit, to avoid the above disadvantages. These are generally ties each of'which extends, as a single member, throughthe forms on both sides of the Wall, and after the forms have been removed, the tie is twisted of'at or within the surface of the concrete at ay weak point in the tie provided for that purpose. Such ties, however, involve other disadvantages: on. an average, more than two-thirds of the tie material must be broken offand discarded after being used once, an expensive procedure; to lcompensate for the weak placesneeded in suchfa tie, the whole tie must be relatively heavy for its intendedstrength; the projecting endsof the-tie are a handicap duringthe construction and removal of the forms; and the work of removing the projecting ends involves additional labor.

TheA present tie avoids both of the above two groups of; handicaps: it isvery` quicklyy applied, probably the mosti quicklyy applied of all set-back ties; it employsl a minimum amount of non-re-usable material, and the non-re-usable members are of very inexpensive manufacture; the re-usablemembers are also quite simple, and w-ill compare favorably in cost with other re-usable recess-forming anchor members for concrete-form ties; andisince the overlap of` the parts at the joints within the concreteis'relatively slightg, the recesses need beonly relatively; shallowfor any given requiredV set-backv of the endszofftheembedd'ed part fromy the` face of the. concrete.

Fory

note-worthy featureof: present; invention is that when ythesetties areused, the forms andthe projecting portions 4the anchory members of; the presentY tie is made possible through these fourf novel features embodied in this tie: Hirst, an anchor; which isL disengaged from the permai neatly/embedded member, orrlink, by a rotaryl movement, ist retable, on aniedge or corner-r of the. concrete afterthe rwice latter has partly or completely set, thus dispensing with any need for a pivot, shaft, bolt, or pin about which to rotate the anchor, and for a mounting for any rotationcentering means.` With a structure likethat used in this device, this leaves the anchor removable even when the form is in place, which appears to be unique among rotatable anchors other than boltv anchors.

Second, the embedded portion of the anchor has substantially the form of a quadrantal sectori of a` circle, which enables one to withdraw the anchor from the concrete with a direct outwardv movement after it, has been rotated merely enough to disengage it' from thelink, in contradistinction to rotatable anchors used in other ties where an engagement prong has to be drawn by a rotary movement through a relatively long passage in they concrete.

Third, an arrangement wherebyy the anchor may be released from its engagement with the back of the form through the movement of an off-set outer end portion of the anchor when the latter is rotated, as willy be further explained.

Fourth, a simple and effective-locking device for maintaining the connection between they link and the anchor while the tie is in active operation, which willr also be further explained.

ln brief, the invention consists of av non-re-usable link or equivalent structure made from a light rod, aheavy wire, or other material, which link hooks onto aprojection on a re-usable anchor member at. either end, the connections being within theconcrete; the anchor members engage the back of the frame of the forms and are so constructed that they may be rotated to a-limited-extent, such rotation yeffecting a disengagement of the anchors from the link; A lockingy pin, which may be a nail, prevents such disengagement while the pin is in place. The anchors are preferably made of malleable iron.

The views of theaccompanying drawing may be briey described as follows:

Figure 1 is a top view of'theprimary member or link shown separately.

Figure 2 is a side view. of the same.

Figure` 3 is a top View: of oneof the anchormembers in place in a form, with a portionof a connected link shown.

Figure 4 is a side, view corresponding toFigure 3.

The primary member'or' link may be made fromlight rodmaterial or heavy` Wire in a shapee resembling an elongated chain link, as indicated in1Fi`guresz1 and' 2. The link is indicated in;A the, various viewsy by the reference numeral 1. The ends of thezmaterial forming the link may be lapped andithen electrically welded; Otherf'orms for the link are possible, however; thus, one might use a single stem witha loop at either: end, orv a at bar with holes punchedirrthe ends.

The two anchors inv ai tiel are of identical shape. An anchor is in Figures 3: and 4 designated by tlre'reference numeral 2. As seen in Figures 3v and 4, the anchor Z has -a portion 3l` embedded: in theconcreteC.V This portion has a formwhich, as; viewed from the side, is. substantially, though preferably not, absolutely, that of" a quadrantal sector of ia; circle. The. arc ofi thisf figure, which gure it is convenient to designate as a sector, is preferably not ain-absolutely,4v true circular curve, but an involute spiral, or. some similar curve, so that'v a4 slight amount ofrotationV of theV sector about its' vertex will eliminate the peripheral friction' which otherwise would be a hindrance throughout` all ofV the rotation necessary to free the anchor from its engagementv with the link. As may be seen in- Figure 3, the portion 3 tapersfrom a, point opposite the surface of` the concreteto the: inner endwhere it connects withrthe'linkg: with such'` a taper .of the holes 4.4, indicated by broken lines.

-after the concrete is set.

.tremity of portion 3, the general direction of this projection being parallel vwith the arc of the sector.

Through the upper part 3.2 of the portion 3, lying outside of the fnotch 3.3, is a hole 3.4, indicated by broken lines.

`The portion 4 of the anchor 2 extends from the surface of the concrete, that is, from the face of the form sheathing, to the outside or backside of the form. At a right angle across the outer end of the k.anchor is a bar 4.1 which engages the stud St. Bar 4.1 extends laterally in both directions, so that the anchor may readi- .ly beused on either side of a stud. The anchor is held in place by the sides of a rectangular hole or slot H in the form sheathing Sh, through which hole the anchor extends, and by a nail 7 driven into the stud through one The nail may be driven in part way and then bent over, leaving it easy to pull later. What appears to be a small extension of part 3.2 of portion 3, which overlaps the form in the upper part of hole H, has two functions: it helps to keep the anchor in its proper position in the form, and itl helps to prevent leakage in this part of the said hole. However, since it lies outside of the surface of the concrete, it really belongs to portion 4 of the anchor, rather than to portion 3, and really does not form part of the sector. l

`The, shoulders indicated at 4.2 serve to support the sheathing along the greater portion of the vertical edges of the hole or slot H against the pressure of the concrete, leaving only a smaller portion at the top of the hole unsupported.

After the anchor 2 has been placed in the form, the link 1 is looped over the projection 3.1 and a pin 6, which may be a nail, is driven through the hole 3.4. The pin 6 extends to the projection 3.1 and overlies the end of the link 1, thus maintaining the connection between the anchor and the link as long as the pin remains in place. The pin 6 needs to t only loosely in the hole 3.4, but the hole is so positioned that the pin must bend slightly when it is being driven into place, so that the outer end will spring into the'small depression 4.3 in the top surface of the portion 4 of the anchor, thus preventing the :pin from accidentally working out of place. Instead of having the pin retained by a depression like 4.3 we may, if we want to do so, use any other irregularity in the top surface of the anchor which will engage the outer end of the pin; thus, a slight projection which would hook behind the end of the pin would serve the purpose.

It may be noted that the portion of the pin 6 lying Within the hole 3.4 is prevented from bonding with the concrete by the surrounding material of the embedded sector, which makes possible the withdrawal. of the pin As may be seen in Figures 3 and 4 of the drawing, a small portion of the pin 6, the extreme inner end, is, and must be, exposed to the concrete. However, since the exposed portion is very short, no elective bonding of the pin with the concrete, bonding to such `an extent that the bond may not readily be broken by a moderate pull on the outer end of the pin, can take place. Even an exposed portion of the pin a half inch long would not effect a prohibitive amount of bonding.

The above-described procedure for placing the anchor vand connecting it with the link is essentially the same for both sides or" the wall. This is also true for the procedure of removing the anchor after the concrete has partly or completely set, which we shall now consider.

The pin 6 may be removed with a pair of pliers, or in case a nail is used, with la claw-hammer or a claw-bar, which will also serve to remove the nail 7. The anchor may then be rotated by tapping the bottom of

bar

4,1

` be attached to the studs of the forms.

with a hammer. The bottom of bar 4.1 is shown in Figure 4 as being convex; this convexity is intended to prevent the lower edges of the two surfaces which engage the studs from being battered up by hammer blows. The axis of rotation lies at the surface of the concrete opposite the top edge of the hole H. A point representing this axis is in Figure 4 indicated by the numeral 0. The dashed line extending from 0 to 0.1 represents a geometrical plane which is normal to the surface of the concrete and which passes through the axis of rotation. When the anchor is rotated to the extent that the top inner edge of bar 4.1 is brought into coincidence with the plane- 0-0.1, the bar has become free from contact with the stud. The path of the said edge of'bar 4.1 throughout 'the possible rotation is indicated in Figure 4 by the dashed delineation of a circular arc 5 passing through the points 5.1, 5.2, and 5.3. We may note that the clearance between bar 4.1 and' the 4stud becomes progressively greater up to the point 5.2, whence it progressively decreases. However, by the time point'5.3 is reached, and contact between bar 4.1 and the stud is re-established, the anchor will have been completely disconnected from link 1 and may be withdrawn from the concrete and from the form.

The initial displacement of the top inner edge of bar 4.1 from the plane 0-01 is what makes possible a rotation of suicient extent to effect a disconnection of the anchor from the link, and it makes this possible with only a slight effort. We may note that the use of this means for releasing the engagement of the anchor with the back of a stud, and for disconnecting the anchor from the link, need not b'e contined to ties with set-back links v ff In the preceding discussion of the application of the present tie, it has been assumed that the anchors would However, it will e seen that the anchors may also readily be attached to wales, horizontal stilening members placed outside of the studs, when this is desirable. They would be posited so as to make the axis of rotation vertical. Such anchors have to be long enough to extend. back of the wales, -but in other essential'respects these anchors need not be structurally differentl from those which are applicable to studs.

We may note that after forms constructed with ties of the type here discussed have beenl stripped from a concrete wall, anchors, particularly stud anchors, may be re-inserted in recesses and applied to various. services.

4For instance, a scaffold ledger may be laid on top ot vof various kinds, members equivalent to the anchors except that the projecting portion is modified to tit each special case, may be inserted in recesseslocated in suitable positions and used as attachment means for such iixtures. In some of such cases the projecting portion may be eliminated entirely andthe xtures secured to the embedded sector by a screw in a tapped hole or by other means. As long as the inserted member is prevented from rotating after it has been put in place, it can not come out unless something breaks, which is not likely, since the stress to be sustained would not in normal cases equal that to which such a connection would be subjected n a fast high-head concrete pour.

As herein understood, the word frame used in reference to a concrete form means the set of relatively heavy structural members to which the sheathing constituting the face of the form is attached. As herein used, the directions in and out are understood to mean toward the center of the concrete in questionY and toward the backside of the form, respectively, unless otherwise indicated.V The Vwords inner and outer in the claims are to be interpreted in conformity with this. When herein the locking pin 6 is mentioned as being maintained in its position by a shoulder in the surface of the anchor, the term shoulder means any irregularity in said surface of such nature that it can hook behind the outer end of the locking pin, and thereby prevent this from accidentally sliding outward and prematurely disconnecting the anchor from the link; such shoulder or irregularity may be an edge of a notch or depression, or it may be anything equivalent, such as a projection.

I claim:

l. A concrete-form tie comprising a primary member and a pair of secondary members, said primary member constituting a set-back link joining the said secondary members, each of said secondary members constituting an anchor securing the tie to the forms: said anchor having a portion removably embedded in the concrete, said embedded portion having substantially the form of a quadrantal sector of a circle and having on its inner extremity a projection engaging the said link; the saidv anchor beingrotatable, while the form is in place, on an axis formed yby an edge of the set concrete, said axis lying in the plane forming the surface of the concrete; the said anchor having at its outer end a transverse bar engaging the back of the frame of the form, the position of the engagement before any rotation has taken place being such that all points of the engagement area are displaced from a plane normal to the surface of the concrete and passing through the axis of rotation of the anchor, the said projection beingof such structure and magnitude that a rotation of the anchor involving a movement of the said transverse bar within a distance equal to twice the original displacement of the said bar will effect a disengagement of the said projection from the said link.

2. A concrete-form tie as deiined in claim 1, in which the inner end of the said anchor has a hole accessible from the outside of the form, a removable pin extending through the said hole, said pin engaging the said projection and the said link and maintaining the connection between these.

3. A concrete-form tie comprising a primary member and a pair of secondary members, said primary member constituting a set-back link joining the said secondary members, each of said secondary members constituting an anchor securing the tie to the forms: said anchor having a portion removably embedded in the concrete, said embedded portion having substantially the form of a quadrantal sector of a circle, one of the two radial sides of the said sector lying substantially parallel to and coincident with the surface of the concrete and the second radial side of said sector lying at substantially a right angle to the surface of the concrete, said anchor having a notch extending into it from the said second radial side, the inner side of the said notch being substantially parallel to the arc of the said sector, that portion of the sector lying between the said notch and the arc of the sector extending through, and thereby engaging, one end of the said link; the said embedded portion of the anchor having a hole accessible from the outside of the form, a removable pin extending through the said hole and across the exterior portion of the said notch, thereby maintaining the engagement between the said link and the said anchor.

4. A concrete-form tie as defined in claim 3, in which the non-embedded portion of the said anchor has a shoulder in its surface, the position of the said shoulder and the alignment of the said hole being such that the outer end of the said pin bears against the said shoulder, the pin being thereby maintained in its position.

5. A concrete-form tie as defined in claim 3, in which the portion of the said anchor through which the said pin passes, within the said hole, is of sutlicient extent to cover and protect from bonding with the concrete the major portion of that part of the said pin which lies within the surface of the concrete.

6. An anchoring device for attaching xtures to concrete Walls, said device having a primary member consisting of a set-back link permanently embedded in the concrete, and a removable secondary member extending into the concrete and connecting with the said primary member: the portion of the said secondary member which extends into the concrete having substantially the form of a quadrantal sector of a circle, one of the two radial sides of the said sector lying substantially vparallel to the surface of the concrete and the second References Cited in the le of this patent UNITED STATES PATENTS 871,327 Dietrichs Nov. 19, 1907 871,390 Dietrichs Nov. 19, 1907 880,201 Dietrichs Feb. 25, 1908 1,237,999 Burnett Aug. 21, 1917 1,486,147 Kelley Mar. 11, 1924 1,549,632 Trester Aug. 11, 1925 1,981,178 Kavnaugh et al. Nov. 20, 1934 2,750,648

Hallock June 19, 1956