Apparatus for molding fluid seal elements

• US 3,950,119 A
• Filed: 01/14/1974
• Issued: 04/13/1976
• Est. Priority Date: 01/14/1974
• Status: Expired due to Term

• Current Assignee: Chicago Rawhide Manufacturing Company
• Original Assignee: Chicago Rawhide Manufacturing Company
• Inventors: Reichenbach, Jerry D.
• Primary Examiner(s): Husar, Francis S.
• Assistant Examiner(s): Rowold, Carl
• Application Number:
  US05/433,195
• Time in Patent Office: 820 Days
• Field of Search: 425/129, 425/251, 425/252, 425/DIG. 228, 425/450 R, 425/809
• US Class Current: 425/129.1
• CPC Class Codes: B29C 45/14336 Coating a portion of the article, e.g. the edge of the article B29C45/14573 and B29C45/14598 take precedence
• CPC Class Codes: B29D 99/0053 Producing sealings B29D99/0085 takes precedence
• CPC Class Codes: B29K 2021/00 Use of unspecified rubbers as moulding material
• CPC Class Codes: B29L 2031/26 Sealing devices, e.g. packaging for pistons or pipe joints
• CPC Class Codes: Y10S 425/047 Seal ring
• CPC Class Codes: Y10S 425/228 Injection plunger or ram: transfer molding type

Abstract

An apparatus for molding articles, particularly those having a body portion formed from a cured material and bonded to a relatively rigid insert portion. Two mold members are arranged for relative movement along a given axis between open and closed positions. Each of the members includes surfaces at least partly directed towards each other to define in said closed position of the members, a molding cavity between the members. One of the mold members has a part for engaging a relatively rigid insert, so as to form a flash barrier on the insert when it is engaged by the mold part. The mold has surfaces for supporting the insert on at least one of its surfaces. The mold assembly includes a third mold member which is movable relative to both of the other two mold members. The moldable material from which the article is to be formed is received on one mold member, and the other member is reciprocable along a given axis and adapted to apply a predetermined closing force to the first and third members. Springs or other resilient means are disposed between a mold plate and the first mold member, and a second spring is disposed between the third mold member and the mold plate, and the first and third mold members have sealing surfaces engaging each other and separated only by a working clearance. In use, the members respectively first engage the stamping, then the rubber, and finally, under the spring force, move the rubber into the mold and hold it there under a predetermined force.

Claims

1. An apparatus for molding articles having a body portion formed from a cured material and bonded to a relatively rigid insert portion, said apparatus comprising, in combination, first and second mold members arranged for relative movement along a given axis between open and closed positions of said members, each of said members including surfaces at least partly directed towards each other to define therebetween, in said closed position of said members, a molding cavity predetermining the exact shape of the body of said article to be formed, means on said first member for engaging a relatively rigid insert, said engaging means being adapted to form a flash barrier on said insert upon engagement thereof, means on said second member for supporting said insert along at least one surface thereof, a material pressing member movable relative to both said first and second mold members, means on said second mold member for receiving a prepared portion of moldable material from which said article is to be formed, means reciprocable along said given axis for applying a predetermined closing force to said first mold member and said press member, first resilient means disposed between said force applying means and said first mold member, second resilient means disposed between said press member and said force applying means, said first, second mold members and said press member confining said portion of moldable material, said members having mutual sealing surfaces separated from each other by a working clearance, said first and second resilient means having uncompressed, free height positions such that movement of said force applying means causes said first mold member to move from said open position to said closed position, thereby to define said molding cavity between said first and second mold member and said insert, and whereby subsequent movement of said press member causes said press member to engage said material and causes only that material able to be accommodated by said cavity to flow from the area of said material-receiving means into said molding cavity under the force applied by said press member through said second resilient means, the shape of said body portion thereby being determined solely by the predetermined shape of said cavity and not by the amount of moldable material in said portion thereof, the resiliency of said second resilient means limiting the force able to be applied to said material.

2. Apparatus as defined in claim 1 wherein said first mold member and said press member include portions adapted for mutual engagement to limit the amount of relative movement therebetween.

3. Apparatus as defined in claim 1 which includes means adapted to engage a portion of said insert to hold said insert in a desired position of registry within said mold prior to engagement of said insert by said second mold member.

4. An apparatus as defined in claim 1 wherein said first mold member and said press member each includes a cylindrical portion, with the outer surface of said cylindrical portion on said press member slidingly engaging the inner surface of said cylindrical portion of said first member.

5. A compression molding apparatus adapted to form articles from a moldable material that are bonded to a relatively rigid insert, said apparatus comprising a first, stationary mold member having surfaces thereon defining respectively, a portion of a molding cavity, a transfer area, and a material-receiving area, a second mold member movable relative to said first mold member between an open position and a closed position, said second member having surfaces thereon cooperating with said surfaces on said first member to define at least a portion of said molding cavity and a portion of said transfer area, said first and second members in the closed positions thereof combining with said insert to define the shape of said article, means for moving said second member between opened and closed positions along a given axis, first spring means disposed between said moving means and said second mold member, a material pressing member movable along said axis between open and closed positions, second spring means associated with said press member and disposed between said moving means and said press member, said press member having at least one surface adapted, in the movement along said axis between said open and closed positions, to engage a portion of said moldable material disposed in said material-receiving area and to move a portion of said material through said transfer area and into said molding cavity under the force supplied to said press member by said moving means through said second spring means to fill said cavity fully and to leave moldable material not able to be accommodated within said molding cavity outside of said cavity.

6. An apparatus as defined in claim 5 wherein said first and second mold members each includes oppositely directed surfaces adapted to engage an insert disposed therebetween in the closed position of said second mold member to establish flash barriers on said insert and prevent loss of said material from said molding cavity upon application of said mold closing force.