Method of molding elastomeric article

• US 6,802,998 B2
• Filed: 05/11/2001
• Issued: 10/12/2004
• Est. Priority Date: 05/12/2000
• Status: Expired due to Fees

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Ono, Ryo
• Primary Examiner(s): Vargot, Mathieu D.
• Application Number:
  US09/852,681
• Publication Number:
  US 20010054782A1
• Time in Patent Office: 1,250 Days
• Field of Search: 264/315, 264/326, 264/69, 264/40.3, 264/40.6, 425/35, 425/44
• US Class Current: 264/69
• CPC Class Codes: B29C 35/04 using liquids, gas or steam
• CPC Class Codes: B29C 43/104 the mould cavity lying totally outside the axis of symmetry, e.g. toroidal moulds
• CPC Class Codes: B29C 43/56 Compression moulding under special conditions, e.g. vacuum
• CPC Class Codes: B29D 30/0601 Vulcanising tyres; Vulcanising presses for tyres
• CPC Class Codes: B29D 30/0662 Accessories, details or auxiliary operations
• CPC Class Codes: B29L 2030/00 Pneumatic or solid tyres or parts thereof conveyor belts B29L2031/7092; drive belts B29L2031/7094; fourdrinier belts B29L2031/733

Abstract

A method of molding an elastomeric article comprises: putting an elastomeric article in a mold; softening the elastomeric article in the mold by heating the elastomeric article; pressing the elastomeric article against the mold by pressurizing an inside of the elastomeric article by letting a fluid therein; and changing the pressure of said fluid in a short cycle so as to beat the elastomeric article against the mold repeatedly.

Claims

1. A method of molding an elastomeric article comprising

putting an elastomeric article in a mold,

softening the elastomeric article in the mold by heating the elastomeric article,

pressing the elastomeric article against the mold by pressurizing an inside of the elastomeric article by introducing a fluid therein, and

changing the pressure of said fluid in a short cycle so as to beat the elastomeric article against the mold, wherein

said fluid is a heating medium which is introduced into the inside of the elastomeric article to heat the elastomeric article,

the pressure is changed at least two cycles between a maximum pressure P1U for the process of heating the elastomeric article and a lower pressure P1D less than the maximum pressure P1U but not less than ½

times the maximum pressure P1U, and

one cycle of the change in the pressure comprises a decrease of short duration of not more than 10 seconds and an increase of short duration of not more than 10 seconds.

4. The method according to claim 1, 2 or 3, wherein

the number of cycles of the change in the pressure is at most fifty.

5. The method according to claim 1, 2 or 3, wherein

the number of cycles of the change in the pressure is at most twenty.

6. The method according to claim 1, 2 or 3, wherein

the number of cycles of the change in the pressure is at most ten.

7. The method according to claim 1, 2 or 3, wherein

said elastomeric article is a pneumatic tire.

9. The method according to claim 1, or 3, wherein

the heating medium is a gas having a high heat capacity, and the pressurizing medium is an inert gas having a heat capacity lower than the heat capacity of the heating medium.

10. The method according to claim 1 or 3, wherein

in the process of heating the elastomeric article by the heating medium, after the cyclic change in the pressure of the heating medium is made, the pressure is kept substantially constant for a certain length of time.

2. A method of molding an elastomeric article comprising

putting an elastomeric article in a mold,

softening the elastomeric article in the mold by heating the elastomeric article,

pressing the elastomeric article against the mold by pressurizing an inside of the elastomeric article by introducing a fluid therein, and

changing the pressure of said fluid in a short cycle so as to beat the elastomeric article against the mold, wherein

said fluid is a pressurizing medium which is introduced into the inside of the elastomeric article to pressurize the inside of the elastomeric article,

the pressure is changed at least two cycles between a maximum pressure P2U for the process of pressurizing the elastomeric article and a lower pressure P2D less than the maximum pressure P2U, and

one cycle of the change in the pressure comprises a decrease of short duration of not more than 60 seconds and an increase of short duration of not more than 60 seconds.

8. The method according to claim 2 or 3, wherein

one cycle of the change in the pressure comprises a decrease of short duration of not more than 10 seconds and an increase of short duration of not more than 10 seconds.

3. A method of molding an elastomeric article comprising

putting an elastomeric article in a mold,

softening the elastomeric article in the mold by heating the elastomeric article,

pressing the elastomeric article against the mold by pressurizing an inside of the elastomeric article by introducing a fluid therein, and

changing the pressure of said fluid in a short cycle so as to beat the elastomeric article against the mold, wherein

said fluid is a heating medium which is introduced into the inside of the elastomeric article to heat the elastomeric article and

a pressurizing medium which is introduced into the inside of the elastomeric article to pressurize the inside of the elastomeric article,

the pressure of the heating medium is changed at least two cycles between a maximum pressure P1U for the process of heating the elastomeric article and a lower pressure P1D less than the maximum pressure P1U but not less than ½

times the maximum pressure P1U, wherein one cycle of the change in the pressure comprises a decrease of short duration of not more than 60 seconds and an increase of short duration of not more than 60 seconds, and

the pressure of the pressurizing medium is changed at least two cycles between a maximum pressure P2U for the process of pressurizing the elastomeric article and a lower pressure P2D less than the maximum pressure P2U, wherein one cycle of the change in the pressure comprises a decrease of short duration of not more than 60 seconds and an increase of short duration of not more than 60 seconds.