Forming fastener elements
AssigneeVelcro BVBA
InventorsLuis Parellada Armela, Elm Aubà Gomis
Life of this patent
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Abstract
Arrays of male fastener elements are formed by molding preforms in cavities defined in one or more adjacent plates and shaped to mold preform arms that extend to a plate side, such as in a cross-machine direction of a continuous molding process. The preforms may be deformed to flatten their upper surfaces and lengthen the arms. Stems of preforms have molded side surfaces and each have width, measured in the longitudinal direction of the strip, that narrows with distance from the strip surface, and also narrows with distance from a parting line extending from the strip surface to the head between the arms.
Claims24
A method of molding a touch fastener hooking structure, the method comprising
- forming a stack of rings comprising two adjacent, separable molding rings together defining a molding cavity extending inward from an outer surface of the ring stack, the two adjacent molding rings comprising
- a first ring in which the cavity extends only partially through a thickness of the ring at the outer surface of the ring stack, and fully through the thickness of the ring at a depth below the surface of the ring stack;
- and
- a second ring bounding the cavity at the surface of the ring stack;
- filling the molding cavity with resin contiguous with resin disposed on the outer surface of the ring stack to form a resin layer with an integral projection molded in the cavity;
- and then
- withdrawing the projection from the cavity;
- the projection comprising a touch fastener hooking structure having a stem extending from the resin layer to an overhanging head having a distal tip, the stem having a side surface facing the tip and formed against material of the first ring, and the tip formed against a ring on a side of the first ring opposite the second ring.
A method of forming a touch fastener product, the method comprising
- molding a resin strip having a surface from which an array of resin projections integrally extends, each projection having
- a stem extending from the strip surface to
- a distal head having
- at least one arm extending laterally to overhang the strip, the arm having an upper surface extending from the stem to a distal tip;
- and
- a central cap overlying the stem;
- and
- plastically deforming the projections of the molded strip to raise the distal tips of the arms such that the distal tips of the arms project away from the strip surface, and such that the central caps project farther from the strip than inner portions of the upper surfaces of the arms;
- and then
- pressing downward on the resin projections with a heated surface that plastically lowers the raised distal tips of the arms and also melts the central caps, thereby forming male touch fastening elements extending from the strip.
A method of forming a touch fastener product, the method comprising forming a resin strip having a surface from which an array of resin projections integrally extends, each projection having
- a stem extending from the strip surface to
- a distal head having
- at least one arm extending laterally to overhang the strip, the arm having an upper surface rising from the stem to a distal tip;
- and
- a central cap overlying the stem and projecting farther from the strip than an inner portion of the upper surface of the arm;
- and then
- pressing downward on the resin projections with a heated surface that plastically lowers the distal tips of the arms and also melts the central caps, thereby forming male touch fastening elements extending from the strip,
- wherein the distal tips are formed with flanges extending about their perimeters, and wherein pressing downward on the resin projections melts the flanges at the upper surfaces of the arms while retaining the flanges under the arms.
Dependencies are inferred from the claim text.