US 3462114 A
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Description (OCR text may contain errors)
Aug. 19, 1969 w. H. oDELLQsR., ET-"AL 3,462,114
ALUG SCREW FOR cfnIs'l'Ruc'lION FORMS I Filed Nov. 21, 1966 Hal l '2 Flez NvENToRs w/IILDEN H. O'DELL, SR.
' WALDEN H. O'DELL, JR.- 22 ,BY y v y FIGi g s PRIOR ART i ATTORNEYS United States Patent O 3,462,114 LUG SCREW FOR CONSTRUCTION FORMS Walden H. ODell, Sr., 2118 Victor St., St. Louis, Mo. 63104, and Walden H. ODell, Jr., 2595 Cheshire, St. Louis, Mo. 63119 Filed Nov. 21, 1966, Ser. No. 601,279 Int. Cl. E09g 17/06; F16b 35 04 U.S. Cl. 249-195 3 Claims ABSTRACT OF THE DISCLOSURE This invention pertains to an improved lug screw for construction forms, particularly for forms used in the construction field when pouring foundation walls, and the like.
In the construction field after a concrete footing has been poured and set, wooden form sheets are erected in parallel vertical rows and are interconnected by a series of tie-rods which are secured at the ends adjacent the outer surfaces of the forms. The wooden form sheets are provided with spaced horizontally set straps and the tierod ends are headed at the straps. Locking keys are then put in position to interconnect the straps and tie the form sheets together. The locking keys are pivotally mounted on the form sheets by lug screws and other lug screws on adjacent form sheets are provided so. that notches in the locking keys can engage the other lug screws.
The problem which has existed for some time with wooden form sheets is that the lugs screws quickly loosen up or pull out which renders the form sheets useless. In many instances the prevailing lug screws must be tightened up so that eventually the heads are pulled into the wood breaking the wood fibres and permitting water rot to set in. Also it is a problem that the lug screws eventually twist loose and cannot thereafter be tightened. A further problem is that the lug screws are made with the usual right hand threads which promotes loosening when the locking keys are hammered loose at the time of form sheet removal.
It is an object of this invention to provide an improved lug screw that overcomes the problems prevailing with current types of lug screws.
Another object of this invention is to provide an improved lug screw that can 4be used as an original component of form sheets or may be used to replace the older types of lug screws as the latter are rendered useless.
A further object of this invention is to provide an improved lug screw with means which will accurately locate itself in the form sheet, will provide means whereby excessive tightening can be prevented, and which cannot be loosened during the disengagement of the locking keys.
Other objects of this invention will be-more particularly set forth in the following description of a preferred lug screw, reference being directed to the accompanying drawings, wherein:
FIG. 1 is a fragmentary elevational view of a plurality of form sheets set in position on a suitable footing and interconnected by locking keys;
FIG. 2 is a sectional view of the form sheets prior to pouring of the concrete, the view being taken at line 2-2 in FIG. 1;
3,462,l 14 Patented Aug. 19, 1969 FIG. 3 is an enlarged fragmentary view of a locking key and lug screws of this invention;
FIG. 4 is a sectional view taken at line 4--4 in FIG. 3;
FIG. 5 is an enlarged view of the improved lug screw showing details thereof; and
FIG. 6 is a view, similar to FIG. 5 of a prior art type of lug screw.
With reference to FIGS. 1 and 2 of the drawings, it can be seen that the form sheets 10 are set in vertical rows on a suitable footing 11, and the parallel rows of ,form sheets 10 are secured against spreading by a plurality of tie-rods 12. Each form sheet is constructed of wood which is cut to very accurate measurements as to length, width and thickness so that accurately dimensioned poured concrete walls can be erected on the footings 11. As may be seen, the form sheets 10 have a series of strap 13 secured in spaced relation to extend widthwise of each form sheet. The straps 13 are arranged so that they align horizontally, and the adjacent ends of the straps 13 are interconnected by locking keys 14.
Each locking key 14 is formed of a suitable length of strap material (FIG. 3) with a plurality of side open notches 15, 16 and 17, and with a transversely extending slot 18 at one end. The locking key 14 is pivotally secured by its slot 18 on a form sheet 10 by a lug screw 19', and one of the notches (in this case the outermost notch) 15 is engaged on a second lug screw 19a. The remaining notches 16 and 17 are provided to straddle the end of a tie-rod 12, depending on whether the tie-rod end is locate in one form sheet or the adjacent form sheet. In the present case (FIG. 3) the tie-rod end 20 is located in notch 16, but it might be located to fall into notch 17. When properly set into position each locking key engages the lug screws 19 and 19a which, in turn, are engaged in the straps 13. Thus a continuous band is established from one form sheet to another for resisting in tension the load of the concrete in the space (FIG. 2) between rows of such sheets.
It is the prevailing practice to install the locking keys 14 at the same ends of the form sheet straps as shown in FIG. 1, and to pivot the keys counterclockwise into position so that a few blows from a hammer will set them in final position. When it is time to remove the form sheets 19 the worker will hammer the locking keys 14 from below to pivot them loose in a clockwise direction. This action occurs with some tension load on the keys 14 so that the male portion of screws PA of the type shown in FIG. `6, having the normal right hand threads 21 on the male member 22 and matching threads 23 in the socket of the female member 24, will rotate and partially separate due to the friction forces acting on the head 25 of the member 22. Also in the prevailing type of lug screws PA the outer surface of the female member 24 is provided with twisted flutes 26 the more firmly to hold this member against rotation in the wood of the form sheet when threading up on the male member 22. However, the lug screw PA is not made with any means to prevent over tightening because the threads 21 can be screwed up for the full thread length and not bottom in the socket of the female member 24. The tendency always is, when the lug screw PA is loose, to turn the head 25 more tightly and this action draws the head 28 into the form sheet (the head 25 being held by shoulder 29 on the strap 13 in fixed position) breaking the libres and setting up the conditions for water to enter and cause rot. As the wood rot continues the utes 26 no longer hold and the female member can rotate and become permanently loose. The locking key is pivotally mounted on the shoulder 29 so that it may pivot, but when the lug screw PA is tightened the shoulder is drawn tightly against the strap 13 and the locking key is partially held against pivoting movement. 'Ihis is so because there is no provision for holding a set distance between head and head 28. The drawing of head 28 into the wood is objectionable for the reason that it produces an enlarged dimple in the form sheets on the concrete side of the form sheets which leaves an unsightly mark in the nished wall.
The improved lug screw'19 of FIG. 5 overcomes the problems inherent with lug screws PA in a uniquely simple manner. It can be seen that the improved lug screw 19 has a female member 30 formed with a head 31 having a screw driver slot 32 therein. The shank surface of member 30 is smooth, and the socket is provided with left hand threads 33 in its outer portion and with a counter bored recess 34 therebeyond. The cooperating male member 35 is formed with a wrench engaging head 36 having iiats of a thickness to provide substantial wrench faces 37. It is especially important to form the head 36 with wrench engaging flats 37 having a substantial thickness or increase in area as compared with the ordinary lug screw head 25 shown in FIG. 6. A shoulder 38 is provided for pivotally supporting a locking key by its slot 18, and the shank is provided with left hand threads 39 to engage the threads 33 in female member 30. An extension 40 on the threaded shank 39 is provided to t into and bottom on recess 34 of the female member 30 so that when the members 30 and are fully threaded up there is established a fixed distance between heads 31 and 36, thereby limiting the amount of draw-down of the lug screw members 30 and 35 so that there is avoided the problem of sinking the head 31 into the form sheets.
The foregoing description relating to the lug screw 19 applies equally to lug screws 19a and it will not be necessary to describe the latter.
It is now believed clear in what manner the improved lug screw 19 is uniquely new and different from the prior art type of lug screw, and it is the intent to cover the improved lug screw as broadly as possible in the appended claims.
What is claimed is:
1. A lug screw for construction forms comprising: a pair of cooperating members engaged in a construction form from opposite sides; one of said members having a head, a threaded socket and a smooth outer surface on the socket; the other said member also having a head, a pivot forming shoulder adjacent said head, and a threaded shank extending outwardly from said shoulder to engage with said threaded socket, said pivot forming shoulder having a diameter larger than said threaded shank; and
means on said pair of members limiting the distance between said heads upon threading said members together, said distance limiting means includes a counterbore in said socket of lesser diameter than said threaded socket and an extension on said shank of lesser diameter than and adapted to bottom in said counterbore.
2. In combination with a plurality of adjacent construction form sheets, each having a plurality of tension straps secured thereto and locking keys pivotally mounted thereon by lug screws to swing into engagement with other lug screws on adjacent form sheets, the improvement in said lug screws wherein each lug screw comprises: a pair of` cooperating members engaged in the form sheets from opposite faces; one of said members having a countersunk head and an internally threaded socket; the other of said members having a wrench engaging head, a pivot forming shoulder adjacent said wrench engaging head to freely engage a locking key, and an axially extending threaded shank adjacent said shoulder to engage in said threaded socket; and means on said pair of members effective to limit the distance between said heads upon threading said members together to prevent obstructing the free engagement of the locking key, said distance limiting means includes a counterborc in said socket and an axial extension on said shank adapted to bottom in said counterbore.
3. In the combination of claim 2 where the locking keys swing in a predetermined circular direction out of engagement with lug screws, the improvement wherein the threads of said socket and on said shank are of the opposite hand to said predetermined circular direction of swing of the locking keys.
References Cited UNITED STATES PATENTS 1,644,018 10/1927 Hull 85-4 X 1,890,725 12/1932 Echols 2,898,659 8/1959 Shoemaker 249-195 X 3,055,076 9/ 1962 VanHelder et al 24945 3,115,804 12/1963 Johnson 85-4 FOREIGN PATENTS 442,935 9/ 1912 France.
J. HOWARD FLINT, JR., Primary Examiner U.S. Cl. X.R.