ASTM D7142-05 (R2021) pdf free download.Standard Test Method for Holding Strength of Prong-Ring Attached Snap Fasteners.
1 .1 This test method covers the determination of the holding strength of a prong-ring to the socket or stud of a snap fastener using a tensile testing machine (Option I) or a manual test stand and force-measuring gage (Option 2).
1 .2 This test method is applicable to prong-ring type snap fasteners in garments or to be attached to fabrics intended for use in apparel (see Annex Al).
1 .3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
3. Terminology
3. 1 DefinitionS.
3.1.1 force, n—a physical influence exerted by one body on another which produces acceleration of bodies that are free to move and deformation of bodies that are not free to move.
3. 1 .2 holding strength, n—in snap fasteners, the force required to separate the prong-ring from its attached mating part (socket or stud).
3. 1 .2. 1 Discussion—In this test method, a diametric force is applied which simulates the diametric biting or pinching of a child; however, in practice, the disengaging force used to unsnap a snap fastener is usually applied at the edge of the fastener.
3.1.3 prong-ring type fastenei n—generic name for snap fasteners which usc a multi-pronged ring to penetrate through fabric to mechanically set a matching socket on one side of a closure and to set a matching stud on the facing closure allowing the outer and inner closure facings to be snapped together. (See Fig. 1.)
3.1.4 socket, n—in snap fasteners, the female functional part of the fastener which engages with the stud part of the fastener to form the closure of two parts of the item on which the fastener is used. (See Fig. 1.)
3.1.4.1 Di.scussion—Prong-ring attached socket or stud snap fasteners are designed to he mechanically attached to garments or other items through the deformation interaction of the prong-ring with the socket or stud. Other forms of snap fasteners exist which may he attached to the foundation of the garment or other item by means of sewn threads or adhesive bonding.
3.1.5 strength, n—the property of a material that resists deformation induced by external forces.
3. 1 .5. 1 Discussion—In this standard, the deformation is the separation of the prong-ring from the socket or stud of a snap fastener.ASTM D7142 pdf download.