Ball chain and method of manufacturing the same
AssigneeNamiki Co., Ltd.
InventorsNorio Namiki, Hiroji Takahashi
Life of this patent
Estimating the term…
Abstract
A ball chain including metal balls with a small wall thickness and can withstand a large tensile load are provided. A method of manufacturing the same includes rounding a piece of metal to form rotation-axis symmetric bodies 22 and connecting the rotation-axis symmetric bodies 22 in a chain-like manner with connecting shafts. Each of the connecting shafts has connecting heads on both end portions. Each of the rotation-axis symmetric bodies 22 has a butt seam 24 in a direction of a rotation axis of the rotation-axis symmetric body and a weld part 25 at at least one part of the butt seam 24.
Claims8
A ball chain obtained by rounding a piece of metal to form metal, hollow and rotation-axis symmetric bodies and connecting said rotation-axis symmetric bodies in a chain-like manner with connecting shafts, each of the connecting shafts having connecting heads on both end portions,
- characterized in that each of said rotation-axis symmetric bodies has a butt seam in a direction of a rotation axis of the rotation-axis symmetric body and a weld portion at at least one part of said butt seam.
A method of manufacturing a ball chain characterized by comprising the steps of:
- passing a metal wire through a connecting shaft metal mold to form a shape of a connecting shaft wire in which connecting shafts are joined together in a linear fashion;
- delivering a metal tape and said connecting shaft wire to a drawing die having a positioning means for determining positioning of a feed-in position of said connecting shaft wire and a feed-in position and a feed-in angle of a metal tape;
- drawing said metal tape using said drawing die to form a metal tube with said connecting shaft wire contained therein after said metal tape and said connecting shaft wire are rotated by a predetermined angle at a time with respect to said connecting shaft wire;
- welding a butt seam of said metal tube by irradiating a laser, or by performing TIG welding, on said butt seam in synchronization with a rotation of said metal tube when said butt seam of said metal tube is rotated to a predetermined position;
- forming said metal tube into a shape of a ball chain structure in which a plurality of rotation-axis symmetric bodies are joined together in a linear fashion, said rotation-axis symmetric bodies respectively containing connecting heads of each connecting shaft of said connecting shaft wire, by delivering said metal tube and said connecting shaft wire into a rotation-axis-symmetric-body forming metal mold and rotating said metal tube and said connecting shaft wire by a predetermined angle at a time;
- and
- separating a joint of each rotation-axis symmetric body of said ball chain structure and a joint of each connecting shaft of said connecting shaft wire.
A method of manufacturing a ball chain characterized by comprising the steps of:
- passing a metal wire through a connecting shaft metal mold to form a shape of a connecting shaft wire in which connecting shafts are joined together in a linear fashion;
- delivering a metal tape and said connecting shaft wire to a drawing die having a positioning means for determining positioning of a feed-in position of said connecting shaft wire and a feed-in position and a feed-in angle of a metal tape;
- drawing said metal tape using said drawing die to form a metal tube with said connecting shaft wire contained therein after said metal tape and said connecting shaft wire are rotated by a predetermined angle at a time with respect to said connecting shaft wire;
- welding a butt seam of said metal tube using a laser welding torch, or a TIG welding torch, which rotates together with a rotation of said drawing die and performs welding from a constant position relative to said drawing die;
- forming said metal tube into a shape of a ball chain structure in which a plurality of the rotation-axis symmetric bodies are joined together in a linear fashion, said rotation-axis symmetric bodies respectively containing connecting heads of each connecting shaft of said connecting shaft wire, by delivering said metal tube and said connecting shaft wire into a rotation-axis-symmetric-body forming metal mold and rotating said metal tube and said connecting shaft wire by a predetermined angle at a time;
- and
- separating a joint of each rotation-axis symmetric body of said ball chain structure and a joint of each connecting shaft of said connecting shaft wire.
Dependencies are inferred from the claim text.