US2274161A - Molded slider for slide fasteners - Google Patents

Description

Feb. 24, 1942. N. J. POUX MOLDED SLIDER FOR SLIDE FASTENERS Filed June 30, 1938 By ATTORNEYS.

one in that it comprises Patented Feb. 24, 1942 UNITED I STATES PATENT OFFICE Noel J. Poux, Meadville, Pa.,

Inc., a corporation of assignor to Talon, Pennsylvania Application June 30, 1938, Serial No. 216,729

3 Claims.

My invention relates to molded sliders ior slide fasteners.

In the manufacture of sliders from plastic material such as cellulose acetate or cellulose nitrate, the method usually employed is to mold slider bodies in one piece. The shape of a slider from a structural standpoint is a rather unique top and bottom wings which must be held together in accurate fixed spaced relation but which can be connected together only in the narrow central portion at one end of the wings.

It is therefore highly important to make this, neck connection as strong as possible and the many patents in the art of slide fasteners directed to the making of strong necks in metal sliders will attest to this fact. In molded sliders of plastic material the strength of this neck is not as great as the strength of a metal neck in a slider of corresponding size and it-becomes all the more important to maintain uniformity and the maximum possible strength. The thickness of the material in the neck has been made substantially greater than the thickness of the wing material and it has been found in experience that while some of the sliders have suflicient strength there will be considerable variation. 1- have discovered that the strength of the material at the surface of these molded sliders is greater than in the interior and my invention utilizes that fact in producing molded sliders in which the neck will have more uniform thickness and greater strength.

It has also been observed in molded sliders that there will be a depression in the surface of the slider adjacent the neck portion when the neck is molded. This is believed to be due to the shrinkage of the relatively large mass of material in cooling adjacent the neck portion.

My invention also overcomes this difliculty.

In the accompanying drawing I have shown well known and are explained in numerous prior patents. A slider generally designated 1 is moved over the fastener elements in opening or closing the fastener by means of a pull tab 8.

for purposes of illustration one embodiment which my invention may assume in practice. In the drawing: Fig. 1 shows a portion of a slide fastener equipped with my improved slider;

Fig. 2 shows a rear end view of the slider; Fig. 3 shows a vertical longitudinal cross-section; and

Fig. 4 shows a horizontal central crosssection. The slide fastener on which my improved slider is mounted comprises a pair of fabric tapes 5 having flxed on their adjacent edges rows of fastener elements 6. The construction and operation of the fastener elements of this type are The slider body is a one-piece integral molded structure comprising a top wing 8 and a bottom wing I 0, an integral neck connection H, and a lug or loop H! on the top 'wing aflording means for convenient attachment of the pull tab. At least one of the wings in the present instance has side flanges l3 bearing against the ends of the elements and which guide them through the interior channel of the slider. As seen from the rear end of the slider in Fig. 2 the over-all width of the neck is substantially greater than the thickness of the wing material. In the practice heretofore of molding the neck as a solid element, there is a mass of material of substantially greater thickness than the wing material and due to the variable characteristics of the material used, the internal structure of the material in this wide portion of the neck varies and accordingly the strength of the slider is difiicult to control. According to my invention a recess l4 extends from the rear end of the neck well toward its pointed end so that the side walls H of the neck will have a thickness approximately equal to or less than the thickness of the top wing material. The V-shaped neck itself extends well into the wing and its pointed end It is located between the side flanges l3. It is not sufl'lcient for my purpose to have only'a shallow recess, (which has been an incidental result in certain methods of molding sliders heretofore employed), but it is necessary that the recess l4 extend a substantial distance into the neck. Preferably it is rectangular in cross-section at the entrance end, the height of the recess being substantially as great as the distance between the wings. The walls I! of the recess are preferably run parallel up to the tapered portion of the neck and then the walls converge to a point I8 so that the resulting recess has a depth substantially greater than half the total length of the neck. Because it is usual to form the neck in a portion of the slider which extends rearwardly beyond the ends of the flanges l3, it is convenient to have this recess extend to a point substantially in line with the ends of the flanges. While the benefits of my invention may be secured at least to some extent with other forms point of the V so that the maximum thickness oi any section of the neck is substantially less than the over-all width. This results in much greater uniformity of strength and the surface area is very greatly increased. Accordingly, my invention utilizes the material to the greatest possible advantage.

While I have shown and described in this apslide fasteners comprising top and bottom wings,

an integral wing connecting neck extending from one end well into the wings, said neck having a molded-in recess of a length at least half as great as the length of the neck.

2. A non-metallic molded plastic slider for slide fasteners of the class described comprisingtop and bottom wings, an integral connecting neck V-shaped in cross-section extending from the rear end of the slider well into the wings, said neck being hollow with molded surfaces and having walls of substantially uniform thickness apggoximately the same as the thickness of the w s.

3. A one-piece integral non-metallic molded plastic slider for slide fasteners, comprising top and bottom wings, an integral neck connectins the wings at one end for holding them in iixed spaced parallel relation, said neck being V- shaped in horizontal cross-section and having a molded-in" recess extending lengthwise into the neck, the walls of the recess in horizontal crosssection being of substantially uniform thickness and substantially parallel at the entrance end of the recess and converging toward the end of the recess between the converging sides of the neck, the high ratio of molded skin area to volume of material in said neck producing high strength and rigidity therein.

. NOEL J. POUX.

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