Method and apparatus of diametrically expanding metal shafts

• US 6,568,233 B2
• Filed: 01/28/2002
• Issued: 05/27/2003
• Est. Priority Date: 01/20/1999
• Status: Expired due to Term

• Current Assignee: Neturen Company Limited
• Original Assignee: Iura Co., Ltd.
• Inventors: Yamamoto, Keiji, Iura, Tadashi, Mori, Kazuki
• Primary Examiner(s): TOLAN, EDWARD THOMAS
• Application Number:
  US10/055,895
• Publication Number:
  US 20020073755A1
• Time in Patent Office: 484 Days
• Field of Search: 72/94, 721/01, 721/11, 721/25, 723/02, 723/05, 723/16, 723/701.9, 723/702, 723/77
• US Class Current: 72/111
• CPC Class Codes: B21D 17/025 by pressing tubes axially
• CPC Class Codes: B21F 5/00 Upsetting wire or pressing operations affecting the wire cross-sectionin the manufacture of nails or pins B21G3/12
• CPC Class Codes: B21J 5/08 Upsetting
• CPC Class Codes: B21J 9/025 with rolling or wobbling dies
• CPC Class Codes: B21K 1/12 of specially-shaped cross-section

Abstract

Method and apparatus for diametrically expanding a desired part of a metal shaft which can be a rod or a pipe, wherein the apparatus includes a driving rotary section (4) and a driven rotary section (6) arranged at a predetermined distance (D), each of the rotary sections (4) and (6) including a holder for holding a work, a pressing device (8) for pressing the work held by the holders along the length of the apparatus, and a biasing device (7) for declining the axis of the work, so that the work held by the holders at the distance (D) is rotated around its axis, and one of the holders is forced by the pressing device toward the other to carry out the diametral expansion, and then the work is bent back and straightened up.

Claims

1. A method for diametrically expanding a metal shaft, comprising the steps of:

holding the shaft between a pair of holders spaced at a distance (D);

rotating the work around its axis, moving one of the holders toward the other holder so as to compress the work;

biasing one of the holders in a direction which crosses the axis of the other holder, so as to bend the work and build up bulged portions accruing inside the bent portion around the periphery of the work within the distance (D) until a desired expansion is achieved; and

straightening up the work;

wherein the compression is constantly applied to both the inner and outer sides of the work to be bent, and the rotation is initiated at the latest immediately after the bending is started, and the straightening-up is performed under the continued compression and rotation.

2. The method according to claim 1, wherein the compression is relatively low at the initial stage of the diametral expansion, and progressively increases as the diametral expansion advances.

3. An apparatus for diametrically expanding a metal shaft, comprising:

a driving rotary section (4) and a driven rotary section (6) arranged at a predetermined distance, each of the rotary sections comprising holders for securing a work between them;

a driver (5) for operating the driving rotary section (4);

a pressing device (8) for axially compressing the work held by the holders; and

a biasing device (7) for declining the axis of the work;

wherein the pressing device (8) applies the compression to one of the rotary sections (4) and (6), and the biasing device (7) declining the other rotary section (4) or (6).

4. An apparatus for diametrically expanding a a metal shaft, comprising:

a driving rotary section (103) and a driven rotary section (105) arranged at a predetermined distance, each of the rotary sections comprising holders for securing a work therebetween;

a driver (104) for operating the driving rotary section (103);

a pressing device (109) for axially compressing the work held by the holders; and

a biasing device (108) for declining the axis of the work;

wherein either the driving rotary section (103) or the driven rotary section (105) is arranged rotatably around a pivot (107a) provided in a direction perpendicular to the axis of the work, and the rotatably arranged rotary section is supported by the pivot (107a) so as to enable the simultaneous inspection of the inner and outer sides of the bent portion of the work.

5. The apparatus according to claim 4, further comprising a slidable frame (106) provided on the base plate (102), and a rotary framework (107) rotatably connected to the slidable frame (106) through a bearing, and wherein the driving rotary section (103) is secured to the base plate (102) and the driven rotary section (105) is secured to the rotary framework (107).

6. An apparatus for diametrically expanding a metal shaft, comprising:

a driving rotary section (205) and a driven rotary section (225) arranged opposite each other, each of the rotary sections comprising holders for securing a work between them;

a driver (214) for rotating the work held by the holders around its axis;

a first slidable pressing device (206) for causing the driven rotary section (225) to move toward and away from the driving rotary section (203);

a biasing device (230) for rotating the driven rotary section so as to decline with respect to the axis of the holder of the driving rotary section;

a second slidable pressing device (226) for shifting the axis of a pivot rotated by the biasing device (23) toward and away from the driving rotary section; and

a displacing device for shifting the center of rotation between the holders in accordance with a sliding distance covered by each of the first pressing devices (206) and the second pressing device (226).

7. An apparatus for diametrically expanding a metal shaft, comprising:

a driving rotary section (205) and a driven rotary section (225) arranged opposite each other, each of the rotary sections comprising holders for securing a work therebetween;

a driver (214) for rotating the work held by the holders around its axis;

a biasing device (230) for rotating either the driving rotary section (205) or the driven rotary section (225) with respect to the axis of the holder of the other rotary section;

a first slidable pressing device (206) and a second slidable pressing device (226) for moving the driving rotary sections (205) and (225) toward and away from the axis of a pivot (223) rotated by the biasing device (23); and

a displacing device for shifting the axis of the pivot between the holders in accordance with a sliding distance covered by each of the two pressing devices (206) and (226).

8. An apparatus for diametrically expanding a metal shaft, comprising:

a pair of rotary sections (325) and (326);

a holder provided in each of the rotary sections for holding a work;

a sliding device (311) for causing at least one of the rotary sections to move toward and away from the other rotary section;

a biasing device (319) for declining at least one of the rotary sections with respect to the axis of the other rotary section;

a driver (332) for rotating the work held by the holders around its axis; and

a transmission (336) for transmitting the torque of one rotary section to another so as to effect the synchronous rotation of the two rotary sections (325) and (326).

9. The apparatus according to claim 8, wherein the transmission (336) comprises a rotating division in which rotatable brackets (338) are provided, having a pair of splines (339) interposed between them, the splines comprising gear (340) engaged with follower gear (333) provided in the rotating division, thereby transmitting a torque of one of the rotating division to the other.

10. An apparatus for diametrically expanding a metal shaft, comprising:

a driving rotary section (407) provided with a first work holder and being capable of rotating the work held by the holder;

a driven rotary section (415) provided with a second work holder on an opposite side to the holder of the driving rotary section (407) and being capable of moving toward and away from the driving rotary section (407);

a biasing device (428) for declining the second holder with respect to the axis of the first holder; and

a pressing device (409) for pressing the driven rotary section (415) toward the driving rotary section (407);

wherein the driving rotary section is driven by an arrangement in which the first work holder is connected to a chuck of a lathe (M) so as to utilize the torque of the lathe (M).

11. The apparatus according to claim 10, wherein the pressing device (409) is placed between a base plate (403) and a slidable frame (416), and wherein the base plate (403) is provided with a tapered shaft (402), the tapered shaft and the first work holder being connected to the lathe (M), thereby compensating a repulsive force involved in operating the pressing device within the base plate.