US 4,465,448 A · Apparatus for making shoes

Abstract

A method and apparatus for making shoes of the type comprising an injection molded sole which is bonded to a marginal edge portion of a string lasting preferably made of a thermoplastic material. The lasting is held on a last. A radiant heater is automatically positioned below the lasting to preheat the marginal edge portion of the lasting until it is tacky, at about 150.degree.-200.degree. F., after which the heater is withdrawn and the last and the lasting are positioned at the top of a sole mold. Injection molding apparatus injects a molten thermoplastic sole material, such as polyvinyl chloride, at high temperatures of about 300.degree.-380.degree. F. into a sole cavity formed in the sole mold were the molten material bonds to the marginal edge portion of the lasting to form a completed shoe. The completed shoe is cooled by transferring it from the last which was employed during the molding operation to a cooling last separate from the machine. The completed shoe is rapidly cooled to down below 45.degree. F. in less than three minutes. The steps of preheating the lasting prior to molding the sole, and keeping the completed shoe warm until after injection molding whereupon the shoe is removed from the last and rapidly cooled on a separate cooling last provides a secure bond of the lasting and the sole as well as maintaining the desired shape of the completed shoe.

Claims26

Dependent claims

Apparatus for making shoes of the type comprising an injection molded sole which is bonded to a marginal edge portion of a string lasting made of a thermoplastic material, comprising:

a first last for holding said lasting;
a sole mold having a cavity for receiving a molten thermoplastic material for forming said sole, said sole mold being adaptable to be closed at its top by said first last;
means for preheating the lower surface of said marginal edge portion of said lasting until it is in a tacky condition;
means for positioning said preheated lasting and said first last at said top of said sole mold;
means for injecting a molten thermoplastic material into said cavity of said sole mold whereby said molten material bonds to said marginal edge portion of said lasting to form a completed shoe, and
a cooling last comprising a second last for mounting and holding said completed shoe thereon after said shoe is removed for said first last, said cooling last having means for rapidly cooling said completed shoe to a temperature substantially below room temperature;
whereby a secure bonding of said lasting with said injection molded sole is provided as well as maintaining the desired shape of the completed shoe, said means for preheating said marginal edge portion of said lasting including radiant heater element means, a reflecting wall supported at one side of said heater element means for reflecting heat toward said lasting, and means for positioning said heater element means and reflecting wall adjacent said lasting for preheating thereof, and means for retracting said heater element means and reflecting wall from the preheating position, after heating said marginal edge portion of said lasting, to a retracted position away from said lasting.

4 more elements

In an injection molding apparatus for the manufacture of shoes of the type comprising a string lasting bonded to an injection molded sole, said apparatus comprising a rotatable table, a plurality of mold assemblies mounted on said table, each of said mold assemblies having a cavity for receiving a molten thermoplastic material for forming a shoe bottom, an injection channel in each mold assembly leading into said mold cavity, injection means for injecting a molten thermoplastic material into said cavity of said mold assembly, means for locating said table for successively aligning said injection channel of each mold assembly with an outlet of said injection means for injecting said molten thermoplastic material into said cavity, means for preheating said lasting and means for removing the shoe bottom from said cavity after said material has set, the improvment of which comprises means located at the position adjacent said rotatable table for automatically removing a sprue formed of the residue of thermoplastic material remaining in said injection channel in said mold assembly after removal of said shoe bottom formed in said cavity, said automatic sprue removal means operatively connected to said preheating means, said automatic sprue removal means including a pincher assembly having finger means for grasping said sprue, means for extending said pincher assembly to a position adjacent said mold assembly when said mold assembly on said table is adjacent to said pincher assembly, control means for activating said finger means for grasping said sprue, and means for retracting said pincher assembly to a position away from said mold assembly whereby said sprue is pulled out of said injection channel, said preheating means being removable by said retracting means.

Dependencies are inferred from the claim text.

Apparatus for making shoes

Life of this patent

Apparatus for making shoes

Life of this patent

Abstract

Claims26