US2928170A

US2928170A - Method for making form ties

Info

Publication number: US2928170A
Application number: US615781A
Authority: US
Inventors: James A Mclaughlin
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-04-16
Filing date: 1956-10-15
Publication date: 1960-03-15
Anticipated expiration: 1977-03-15

Description

March 15, 1960 J. A. MCLAUGHLIN METHOD FOR MAKING FORM TIES Original Filed April 16. 1953 iq.E.

2,928,170 g 1 METHOD FOR MAKING FORM TIES James A. McLaughlin, Sacramento, Calif.

Original application April16, 1953, Serial No. 349,194, new Patent No. 2,775,018, dated December 25, 1956. Divided and this application October 15, 1956, Serial No. 615,781

2 Claims. c1. 29-444 United tes Pati l o i ;'A particularly advantageous application of an article manufactured by the method of the present invention lies in the field of concrete fabricaiton and the following-dis cussion is referenced thereto. As is well known in the aforementioned art, concrete slabs are formed between a pair of parallel spaced panels and tie means are employed to prevent relative movement between the panel s. Conventionally such tie means comprise a plurality of rods or bars which traverse the space between'thepanels and pass through suitable apertures formed in the latter,

To preventinward displacement of the panels prior to filling of the intervening space with concrete the tie.rods"- are provided with stop means such as a flange or washer inward of the panels. Following concrete pouring and hardening, the panels are removed leaving rod ends extending from the concrete and these are normally broken off by twisting and bending, appropriately weakened rod portions facilitating such an operation. 7

A difiiculty that is-encountered in the foregoing concrete slab fabrication lies in the fixing of the rod flange or washer in the concreteso that rod twisting is quite difficult. I have found that an optimum arrangement lies in fixing a washer or the like about the tie rod against axial displacement in either direction and .yetproviding for relative rotation of washer and-rod. By this means the panels and rod are readily fixed in position without possibility of relative displacement and yet subsequent rod twisting for breakage is not retarded by the washer 7 Following rod breakage aisharp outward thereabout. tug on .the rod suffices to pull the washer from the concrete surface. v

The method of the present invention is particularly adapted to rotatably mount a washer orthe like upon a transpiercing rod while fixing the washer against displacement axially of the rod. Furthremore, in order for the resultant product to be sufiiciently inexpensive for such an application as that discussed above it is required that a minimum of elements be employed and that only simple inexpensive and rapid operations be involved.

It is an object of the present invention to provide a method of mounting an annular member upon a transpiercing rod for rotation thereabout and having limited axial displacement therealong than rod and annulus.

It is another object of the present invention to provide a simple and inexpensive process for manufacturing tie rods of the character described. f

Yet another object of the present invention 15 to provide a simple method of manufacturing tie devices of the type describedin which a rotatable washer is positioned on a rod, and in which portions of the rod on either side without elements other e 2,928,170 Patented Mar. 15, 1960 adopted withinthe scope of theinvention as set forth in. p

the claims. s

Referring to said drawing:

Figure 1 is a cross-sectional side elevation of a concrete wall section',-'illustrating my improved. spacer tie rod in operative position on the building forms.

Figure 2 isa side elevational view of a portion of the rod with the stop means placed thereon prior to carrying out the further: steps in my method of constructing the finished device.

Figure 3 is an-endview taken substantially in the plane indicated by line 33 of Figure 2. '35

Figures 4, 5, and 6 are views similar to Figure 2 generallyv illustrating the successive steps in carrying out my improved processor method of manufacture.

Considering now the details of the improved process of the present invention and referring to the diagrammatic representation of the. steps thereof in Figures 2 to 6, there'will be seen to be initially provided a rod 19 upon 'whi'ch an annular member such as a washer 22 is to' be mounted. As shown-in Figure 2 the desired position of the washer 22vupon the .rod 19 is first determined and the washer then so positioned, with the rod extending through a central washer aperture 23 which is somewhat larger than the rod so that the washer is freely rotatable thereon. The'rod is then heated in that portion thereof extending through the washer and'immediately adjacent same on both sides thereof, the; heated rod portion being indicated by the dashed lines H in Figure 4. This heating may be accomplished by any suitable means such as electrical resistance, induction, open flame or otherwise and is continued until the rod reaches a readily pressure deformable state i.e., red hot in the case of iron bar. It will be appreciated that the foregoing steps are reversible in that the washer 22 may be inserted upon the rod over theheated portion thereofif such is desired.

While the rod is in a heatedcondition'; an inward axial force F is applied to the-rod from opposite sides of the washer 22. Thisforce is s'uflicient to compress and deform the heated metal on both sides of the washer into the r'aidally enlarged portions 24, but as will be seen in Figure 5, suchportions are in immediate adjacent relationship to the sides of the washer, and the rod area 31 disposed intermediate portions 24 will likewise be radially enlarged to fill the washer aperture 23. This deformation will result in providing the-desired axial stop portions 24 for. the washer, but will not permit the necessary free rotation of the washer onthe rod.

Accordingly; as an important feature of my invention, the next step in the method includes a radial'and axial freeing of the washer on the rod, while still retaining the" desired stop portions 24. This final step, which is indicated by Figure 6 of the drawing, comprises the application of outward and opposed axial loads L to the rod 19 from opposite sides of the washer while the rod is still in a heated condition. Such load will result in an axial separation of portions 24 away from the sides of the washer, and at the same time stretches and reduces the diameter of rod area 31 to less than that of the washer aperture whereby the washer is again capable of relative rotation on the rod, although positively limited to a slight amount of axial movement therealong. The exact degree I of axial movement will naturally be determined by the extent of load L and the resulting stretching of the rod, but it is preferable to only stretch the rod sufliciently to merely move the washer and portions 24 apart from each other. Desirably, the rod diameter between the flange portions 24 will be slightly larger than the rod diameter on the other side of portions 24 in order to compensate for the loss of cold working strength which occurs upon heating of the rod in this area.

.As an example of the 'use of the article formed by the present invention, reference is made to Figure 1 showing the tie rods employed in the fabrication of concrete walls or slabs. As illustratedtherein the tie rod, generally indicated by the numeral 12, is shown in position on a portion of concrete wall 13 undergoing construction. The

- concrete is'maint-ained between parallel spaced panels or sheathing 14 during the placing period, and such panels are secured in fixed spaced relationship by means of tie rod 32, vertically extending studs 16, horizontal wales 17, and locking wedges 18 as will be presently explained.

Rod 12 is preferably constructed of generally cylindrical body 19, and is arranged to traversezthe spacing between panels 14, pass through apertures 20 formed in the latter, and extend past the studs and wales for engagement with wedge 18. As will be noted, the rod may be provided with flattened portions 21 to. resist rotary movement of the rod after the concrete has set, and is further provided with stop means to prevent axially inward movement of panels 14. As here shown, such stop means comprises an annular disk or washer 22 having a central opening 23 slightly larger than that of body 19, as previously described; The. latter is provided with radially enlarged ofiset portions 24 disposed on each side of the washer and slightly spaced therefrom, whereby the. washer will be free to rotate while still being restrained against axial displacement.

' In conventional construction, the apertures20 must be or" a size to permit passage of the washer 22 therethrough, and the studs 16 are laterally spaced from the rods. Usually, double 2 x 4 wales 17 are used, one on each side of the rods, and the wedge locked into place with the outer surface of the wales and an enlarged head 26 at the distal end of therod. In stripping the forms, after the concrete has hardened, the wedges, Wales, studs and panels are removed in that order, leaving a relatively lengthy piece of rod protruding from the opposed surfaces of the wall 13.

It is in connection with the removal ofsuch exposed rod ends that the importance of the rotation of washer 22 becomes apparent. To remove the rod ends, the latter are bent at thewall surface, to form a bell crank for imparting torque to that portion of the rod end embedded in the concrete. With the leverage thus developed, the outward embedded portion of the rod is then twisted until broken at a frangible area effected by a diametrically reduced rod portion or breakback 27, rotation of the center section of rod 12 being effectively prevented the while by flattened portions 21 being .embedded in the hardened concrete. If the washer was rigidly secured to the rod, in twisting the latter, it would not only be necessary to break the bond between the rod and concrete, but it would be likewise necessary to break the greater bond between the larger washer and concrete. The excessive torque demanded by the washer bond usually results in twisting off of therod outsidethe washer, rather than at the intended neck. .By virtue of the relative rotation, the rod may be twisted until the latter breaks at portion 27, and then as the washer has at most only a thin film of concrete thereover, it is not too difiicult to pull the washer free from the wall with the broken end portion of the rod. The holes left in the wall by the removal of the washers may then be filled with any suitable material such as dry pack concrete which is driven into the hole with a hammer, and being almost dry will not shrink after drying, and fall out of the hole, as would mortar.

It was previously mentioned that after the forms are assembled, it is only necessary to prevent inward movement of the washers, as the inward panel load is dependent thereon. However, in the erection of the forms, it is equally important that the washers are prevented against outward axial movement, and for this reason, it is important that enlarged portions 24 are disposed adjacent each side of the washer. If the outer deformed portion Was deleted, and the tie passed through opposed holes in the panels, it=would be very easy for the washer to slide axiallyoutwardly through its associated panel-aperture, even though the other of the apertures can boot a size smaller than that of the Washer. This, of course, would result in no washer being present to perform its required and essential inward load bearing functions, or would require poking the washer back through the hole to the inside of the sheathing with some slim tool, at the expense of considerable labor.

What is claimed is:

1. A process for locking a washer upon a rod for rotation thereon comprising the steps of heating said rodat the desired washer locationto a temperature of pressure deformation, slidably inserting said rod in a washer to position the latterat said heated rod portion, applying an axial compression force to said rod whereby said rod will 5 be expanded on both sides of said washer to thereby limit axial displacement of the washer on the rod, and immediately applying an axial tension force to said rod for elongating same between said expanded portions to the extent that the washer is freed to rotate in captivity on said rod.

2. A process for mounting a washer or the like for rotation and limited axial movement on a rod comprising the steps of inserting the rod through-the washer aperture to place the washer in a desired location on the rod, heating the rod at such location to a temperature permitting ready deformation of the rod, applying an axial compressive force to said rod whereby the rodportion within the'washer aperture will be expanded and enlargements of the rod will be formed at each side of and in substantial engagement with the washer, and then applying anaxial tensional force to the rod whereby the expanded portion within the rod Will be substantially restored to its original relatively contracted form and the enlargements will become released from the washer to thereby permit the latter to rotate about the rod.

References Cited in the file of this patent UNITED STATES PATENTS i,382,052 .Birrell June 21, 1921 2,107,130 'Schcnk Feb. 1, 1933 2,199,879 Deroche: May 7, 1940 2,356,864 Kirk 'Aug. 29, 1944 2,366,756 iSpencer 'Jan. 9, 194 5 in-II...