# US 12,000,422 B2 · Crimp securing structure of bolt, crimp securing method for crimp bolt, and crimping die

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- Number: US 12,000,422 B2
- Document ID: US12000422B2
- Status: Granted
- Kind: B2
- Application number: 17/933,165
- Filed: 2022-09-19
- Published: 2023-01-19
- Granted: 2024-06-04
- Earliest claimed: 2020-06-19
- Assignees: Aoyama Seisakusho Co., Ltd.
- Applicants: Aoyama Seisakusho Co., Ltd.
- Inventors: Dan Kitajima; Kazuhiro Koga; Yuichi Katsumata
- Web page: https://patentgrep.com/patent/US12000422B2

## CPC

- F16B 35/04: with specially-shaped head or shaft in order to fix the bolt on or in an object (locking the bolt against turning in the object by the use of accessory parts F16B39/00)
- F16B 35/06: Specially-shaped heads (special shape in order to rotate the bolt F16B23/00 {; separate hook adaptors for bolts F16B43/025})
- B21D 39/00: Application of procedures in order to connect objects or parts, e.g. coating with sheet metal otherwise than by plating ({joining mitred profiles B21D53/745; } riveting B21J; uniting components by forging or pressing to form integral members B21K25/00; welding B23K; press-fitting, force-fitting, or shrinking in general B23P11/00, B21D19/00; by adhesives F16B11/00 {; Connections as such F16L, F16B}); Tube expanders
- F16B 37/068: {by deforming the material of the support, e.g. the sheet or plate}
- F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D)
- B21D: WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (working or processing of wire B21F)

## Abstract

Provided is a crimp securing structure of a bolt in which a crimp bolt 10 having a crimping recess 13 on the upper surface of the head is crimped onto a metal sheet 30. The thickness of a metal material press-fitted into the crimping recess 13 of the crimp bolt is made smaller at the peripheral edge of the crimping recess 13 and is made larger in the center portion thereof. In order to obtain this crimp securing structure, a crimping die 20 in which a stress-relief recess 23 is formed in a center portion of a convex portion is used to prevent the occurrence of excessive local stress in the crimping recess 13.

## Claims

### Claim 1

A crimp securing structure of a bolt in which a crimp bolt is crimped onto a metal sheet while the crimp bolt is not caused to penetrate the metal sheet, wherein
the crimp bolt has a crimping recess having a flat bottom surface on an upper surface of a head of the crimp bolt and a peripheral inner surface having a tapered shape expanding toward the flat bottom surface of the crimping recess, and
a thickness of a metal material press-fitted into the crimping recess is made smaller at a peripheral edge of the crimping recess and is made larger in a center portion of the crimping recess.

### Claim 2 (depends on 1)

A crimp securing method for forming the crimp securing structure according to claim 1, the crimp securing method comprising:
placing the crimp bolt on a front surface of the metal sheet with the head facing downward;
placing a crimping die having a circular convex portion on and extending outwardly from a bottom surface of the die and a stress-relief recess formed in a center portion of the convex portion, on a back surface of the metal sheet;
driving the crimp bolt into the metal sheet by a punch while the crimp bolt is not caused to penetrate the metal sheet; and
press-fitting a metal material into the crimping recess by the convex portion on the surface of the die.

### Claim 3 (depends on 2)

A crimping die used in the crimping securing method according to claim 2, comprising a convex portion having a circular shape formed on and extending outwardly from a bottom surface of the die, and a stress-relief recess formed in a center portion of the convex portion.

### Claim 4 (depends on 3)

The crimping die of claim 3, wherein the shape of the bottom surface of the stress-relief recess is selected from the group consisting of flat, conical convex shape, ring-shaped groove or protrusion and trapezoidal protruding shape.

### Claim 5 (depends on 4)

The crimping die of claim 4, wherein the shape of the bottom surface of the stress-relief recess is flat.

### Claim 6 (depends on 5)

The crimping die of claim 5, wherein a height of the bottom surface of the stress-relief recess is intermediate between a height of the bottom surface of the die and a height of the circular convex portion.

### Claim 7 (depends on 1)

The crimp securing structure according to claim 1, wherein the crimp bolt further includes an anti-rotation uneven portion formed on the peripheral inner surface of the crimping recess.