Method for making racket frames
AssigneeAMF Incorporated
InventorsHerbert R. Jenks, deceased, by Betty J. Jenks, executrix
Life of this patent
Estimating the term…
Abstract
Two small diameter fiberglass tubes are rolled on silicone rubber slugs and inserted into a larger cylinder which is then pinched into a figure-8 shape. This is put in the curing mold. When heated the silicone rubber expands to push the fiberglass into contact with mold surfaces. After cooling the slugs can be pulled lengthwise, which reduces their diameter so they are self freeing from within the cured frame.
Claims6
A method of making an all fiberglass racket frame having a general hairpin shape with I-shape cross section, comprising positioning two small inner tubes of prepreg fiberglass turns wound on inner solid silicone rubber rods in a large outer tube of prepreg fiberglass turns at opposite sides of said outer tube in spaced relationship, pinching said outer tube lengthwise thereof into a figure 8 cross section shape with said inner tubes with their inner rods being positioned at opposite ends of said figure 8 cross section shape, mounting said subassembly of figure 8 cross section shape with inner tubes and rods in a multipart mold having an interior cavity corresponding to said hairpin shape with I-shape cross section, heating said mold to cure said fiberglass and cause said silicone rubber to expand whereby said fiberglass is urged with internal pressure against the interior surfaces of said mold to form said fiberglass into said hairpin shape with I-shape cross section having opposite hollow ends interconnected by an integral web, cooling said mold, and then pulling lengthwise on said silicone rubber rods to reduce their diameter to free them from within the formed racket frame.
A method of making an all fiberglass racket frame having a general hairpin shape with I-shape cross section, comprising positioning two small inner tubes of prepreg fiberglass turns wound on inner solid silicone rubber rods in a large outer tube of prepreg fiberglass turns at opposite sides of said outer tube in spaced relationship, pinching said outer tube lengthwise thereof into a figure 8 cross section shape with said inner tubes with their inner rods being positioned at opposite ends of said figure 8 cross section shape, mounting said subassembly of figure 8 cross section shape with inner tubes and rods in a multipart mold having an interior cavity corresponding to said hairpin shape with I-shape cross section, heating said mold to cure said fiberglass and cause said silicone rubber to expand whereby said fiberglass is urged with internal pressure against the interior surfaces of said mold to form said fiberglass into said hairpin shape with I-shape cross section having opposite hollow ends interconnected by an integral web, cooling said mold, and then pulling lengthwise on said silicone rubber rods to reduce their diameter to free them from within the formed racket frame, and wherein said inner tubes with rubber rods are nested in diametrically opposite grooves of a larger solid silicone master rod having said grooves extending lengthwise thereof, said large outer tube being formed about said master rod with said inner tubes with rubber rods nested therein, pulling on the opposite ends of said master rod and outer and inner tubes and inner rods to reduce its diameter to free said master rod from within said large outer tube while still leaving said inner tubes with rods in said outer tube, and then pinching said outer tube to form said figure 8 cross section shape.
A method of making an all fiberglass racket frame having a general hairpin shape with I-shape cross section, comprising positioning two small inner tubes of prepreg fiberglass turns wound on inner solid silicone rubber rods in a large outer tube of prepreg fiberglass turns at opposite sides of said outer tube in spaced relationship, pinching said outer tube lengthwise thereof into a figure 8 cross section shape with said inner tubes with their inner rods being positioned at opposite ends of said figure 8 cross section shape, mounting said subassembly of figure 8 cross section shape with inner tubes and rods in a multipart mold having an interior cavity corresponding to said hairpin shape with I-shape cross section, heating said mold to cure said fiberglass and cause said silicone rubber to expand whereby said fiberglass is urged with internal pressure against the interior surfaces of said mold to form said fiberglass into said hairpin shape with I-shape cross section having opposite hollow ends interconnected by an integral web, cooling said mold, and then pulling lengthwise on said silicone rubber rods to reduce their diameter to free them from within the formed racket frame, and aligning said two inner tubes in spaced parallel relationship with respect to each other with fiberglass spacer strips spanning said inner tubes, inserting the subassembly of said inner tubes with inner rods and spacer strips lengthwise into said outer tube, and then pinching said outer tube into said figure 8 cross section shape.
A method of making an all fiberglass racket frame comprising the step of rolling a strip of longitudinal prepreg fiberglass about a pair of end butted solid silicone rubber rods starting at the lengthwise edge thereof into a fiberglass inner tube having a plurality of turns surrounding said end butted rods, repeating said step to form a second inner tube, positioning said two inner tubes with inner rods inside a larger outer tube of plurality of turns of bias cut woven prepreg fiberglass fabric, pinching said outer tube lengthwise thereof into a figure 8 cross section shape with said inner tubes with inner rods being positioned at opposite ends of said figure 8 shape, positioning said assembly of outer tube with pair of inner tubes and inner rods into a multipart mold having a hairpin shaped cavity with I-cross section shape, heating said mold to cure said fiberglass and cause said silicone rubber rods to expand, cooling said mold to shrink said rods, and then pulling lengthwise on said rods to reduce their diameter to free and withdraw the same from within the cured fiberglass frame.
A method of making an all fiberglass racket frame comprising surrounding a pair of spaced parallel inner tubes of prepreg fiberglass turns having inner solid silicone rubber rods with an outer tube of prepreg fiberglass turns, pinching said outer tube along the length thereof into a figure 8 cross section shape, heating said assembly of outer tube, two inner tubes, and inner rods in a mold having a racket frame shape with I-shape cross section to expand said rods and cure said fiberglass, cooling said mold to shrink said rods, and then withdrawing said rods from the formed racket frame in said mold by lengthwise pulling on the ends of said rods.
A method of making an all fiberglass racket frame comprising surrounding a pair of parallel and spaced solid silicone rubber rods having a plurality of prepreg fiberglass turns wound thereabout into a pair of tubes with another tube of prepreg fiberglass, pinching said another tube lengthwise thereof into a figure 8 cross section having opposite hollow spaced ends connected by an integral web with said rods and their tubes being positioned at said hollow spaced ends, heating said figure 8 assembly of inner rods and their tubes and outer tube in a mold having a racket shaped cavity with I-shape cross section to cure the fiberglass of said turns and expand said rods to urge said fiberglass into intimate pressure contact with the interior surfaces of said mold, and then reducing the temperature of said mold to cool the formed racket frame in said mold and shrink said rods, and then withdrawing said rods from the frame in said mold by stretching the same lengthwise thereof to reduce the diameter of the same.
Dependencies are inferred from the claim text.