Mold for molding discs

• US 5,626,890 A
• Filed: 10/30/1995
• Issued: 05/06/1997
• Est. Priority Date: 11/08/1994
• Status: Expired due to Fees

• Current Assignee: Meiki (Thailand) Co. Ltd. (Japan Steel Works Limited)
• Original Assignee: Meiki (Thailand) Co. Ltd. (Japan Steel Works Limited)
• Inventors: Asai, Ikuo
• Primary Examiner(s): DAVIS, ROBERT B
• Application Number:
  US08/550,468
• Time in Patent Office: 554 Days
• Field of Search: 425/556, 425/810, 425/437, 264/106
• US Class Current: 425/556
• CPC Class Codes: B29C 45/263 with mould wall parts provided with fine grooves or impressions, e.g. for record discs
• CPC Class Codes: B29C 45/2632 Stampers; Mountings thereof
• CPC Class Codes: B29C 45/43 using fluid under pressure
• CPC Class Codes: Y10S 425/81 Sound record

Abstract

In a mold for molding data discs having a stationary cylindrical member and a movable cylindrical member fixed to a stationary moldhalf and movable moldhalf respectively, in each of which a stationary mirror plate and a movable mirror plate are fixed, an outer peripheral ring is set on the outer peripheral surface of the movable mirror plate, having a protrusion in the lower portion of a small inner peripheral surface of the outer peripheral ring for preventing leakage of air blowing into a cavity to release the discs from the stamper.

Claims

1. A mold for molding discs, comprising:

a stationary mold half on which are mounted a stationary cylindrical member and a stationary mirror plate fixed inside thereof, the stationary mold half defining a stationary side wall of a mold cavity when the mold is closed;

a movable mold half on which are mounted a movable cylindrical member and a movable mirror plate fixed inside thereof, the stationary mirror plate concentric with the movable mold half, the movable mold half defining a movable side wall of a mold cavity when the mold is closed;

a stamper set in concentrically on the movable mirror plate;

an outer peripheral ring fixed so that a large inner peripheral surface thereof is in close contact and concentric with the outer peripheral surface of the mirror plate, of which a small inner peripheral surface defines an outer peripheral surface of the mold cavity, having a protrusion at the lower portion of the small inner peripheral surface so as to prevent leakage of blown air along the inner periphery of the outer peripheral ring; and

a first air passage in an interior of the outer peripheral ring, the first air passage connected to a second air passage provided in an interior of the movable cylindrical member, the first air passage and the second air passage to blow air into the mold cavity.

2. A mold for molding discs according to claim 1 wherein the protrusion provided with the outer peripheral ring has a protruding length L along the radius of the mold cavity and with a width W along the thickness of the mold cavity.

3. A mold for molding discs according to claim 2 wherein the protruding length L is 0.1 mm-0.5 mm in length and the width W is 0.1 mm-0.5 mm.

4. A mold for molding discs, comprising:

a movable mold half on which are mounted a movable cylindrical member and a movable mirror plate fixed inside thereof, the movable mold half defining a movable side wall of a mold cavity when the mold is closed;

a stationary mold half on which are mounted a stationary cylindrical member and a stationary mirror plate fixed inside thereof, the movable mirror plate concentric with the stationary mold half, the stationary mold half defining a stationary side wall of a mold cavity when the mold is closed;

a stamper set in concentrically on the stationary mirror plate;

an outer peripheral ring fixed so that a large inner peripheral surface thereof is in close contact and concentric with the outer peripheral surface of the mirror plate, of which a small inner peripheral surface defines an outer peripheral surface of the mold cavity, having a protrusion at the lower portion of the small inner peripheral surface so as to prevent leakage of blown air along the inner periphery of the outer peripheral ring; and

a first air passage in an interior of the outer peripheral ring, the first air passage connected to a second air passage provided in an interior of the stationary cylindrical member, the first air passage and the second air passage to blow air into the mold cavity.

5. A mold for molding discs according to claim 4 wherein the protrusion provided with the outer peripheral ring has a protruding length L along the radius of the mold cavity and with a width W along the thickness of the mold cavity.

6. A mold for molding discs according to claim 5 wherein, the protruding length h is 0.1 mm-0.5 mm in length and the width W is 0.1 mm-0.5 mm.