Composite Separable Strand Winding Form

This invention relates generally to non-corrosive lifting lugs for tanks, and more particularly to a composite separable form for winding a continuous resin-impregnated strand to produce such a lug.

An object of the invention is to provide such a winding form.

In the drawings,

FIG. 1 is a plan view of the assembled winding form of the invention;

FIG. 2 is a front elevational view of the winding form FIG. 1;

FIG. 3 is an end elevational view taken from the left-hand side of FIG. 2, with certain parts omitted;

FIG. 4 is an end elevational view taken from the right hand side of FIG. 2;

FIGS. 5 and 6 are views of a retaining plate and mounting washer assembly of the winding form of FIGS. 1 and 2, taken at right angles to each other;

FIGS. 7 and 8 are views of a guide member of the winding form of FIGS. 1 and 2, taken at right angles to each other;

FIG. 9 is a perspective view of a lifting lug produced on the winding form of FIGS. 1 and 2; and

FIG. 10 is a fragmentary view of a tank having the lifting lug of FIG. 9 mounted thereon.

With respect to the drawings, FIGS. 1, 2, and 4 show a composite separable winding form 20 constructed in accordance with the invention and useful for producing a tank lifting lug 22 shown in FIG. 9. The lifting lug 22 is more fully described in the copending application of Mark E. Greenwood, Ser. No. 829,748, filed Sept. 1, 1977.

The winding form 20 includes a mounting block 24, a pair of strand guide members 26, a pair of retaining plates 28, and means removably securing a member 26 and a plate 28 to each of two opposite end portions of the block 24. The securing means is shown as a bolt 30 and a nut 32, although other securing means could be used. The block 24 is longitudinally apertured to receive the bolt 30.

A strand guide member 26 is more clearly shown in FIGS. 7 and 8 and includes a generally flat, U-shaped body portion 26a having a pair of bent free end portions 26b extending substantially at right angles thereto. Each end portion 26b is provided with an inner flange 26cand an outer flange 26d whereby a strand guiding channel is defined. The flanges 26c are joined to an inner U-shaped flange 26e on the U-shaped body portion 26a, the U-shaped flange 26e having a recess 26f in a lower bright portion thereof for a purpose hereinafter described. The flanges 26d are joined respectively to outer flange portions 26g on the body portion 26a adjacent upper ends of the leg portions thereof.

A strand retaining plate 28 is more clearly shown in FIGS. 5 and 6 and includes a generally rectangular plate portion 28a and a mounting washer portion 28b comprising a washer welded on the lower half of one side to an upper central portion of an adjacent side of the plate portion 28a. The upper central portion of the plate portion 28a is recessed to conform with the inner periphery of the washer portion 28b for reception of the bolt 30. In the assembled strand winding form 20, the upper half of the washer portion 28b of each retaining plate 28 engages the inner U-shaped flange 26e of the respective guide member 26, and the plate portion 28a is received in the recess 26f.

The lifting lug 22 is produced by manually winding a continuous resin-impregnated strand of glass filaments on the strand winding form 20, clearance between the flange portions 26g and the plate portion 28a at each end of the form enabling winding on the inner sides of the plate portions 28a to form the U-shaped portions of the lug. In a preferred procedure before winding is started, two pieces of tape are applied to the winding form 20 at the end portions 26b bridging the gap between the guide members 26. After curing of the resin in the wound lug, the composite form 20 is disassembled to remove the lug 22. Removal of the bolt 30 allows the block 24 to be pulled out from the bottom of the form 20. The guide members 26 may then be moved toward each other to release the U-shaped portions of the lug 22.

FIG. 10 shows a lug 22 secured to a tank 34 and provided with a bolt 36 secured in position by a nut 38. A hook or cable (not shown) is applied to the bolt 36 for a lifting operation on the tank 34. The lug 22 includes a pair of generally flat U-shaped portions 22a and 22b substantially parallel to a first reference plane represented by line A--A in FIG. 10 and a pair of straight connecting portions 22c and 22d parallel to each other and to a second reference plane perpendicular to the first reference plane and represented by the line B--B.

Various modifications may be made in the structure shown and described without departing from the spirit and scope of the invention.