Claims
- 1. The method of forming a bell shape in a heated end of a length of plastic pipe comprising
- positioning a shaped mandrel in the rear of a pressure chamber;
- inserting the pipe end into an opening in the pressure chamber and over the shaped mandrel;
- closing the opening about the pipe end and forming a sealed pressure chamber about the softened pipe end;
- pressurizing the sealed pressure chamber and pressing the softened end against the mandrel;
- setting the softened end against the mandrel for a sufficient time to set a bell shape in the softened end and then releasing the pressure; and
- withdrawing the pipe end from the pressure chamber.
- 2. The method of claim 1 and the further step of forming an internal groove in the bell shape while the pipe end is within the pressure chamber.
- 3. The method of claim 1 wherein the pressing of the softened end against the mandrel is uniform.
- 4. The method of claim 1 which includes urging portions of front, movable plates against the pipe outwardly of the pressure chamber opening.
- 5. The method of claim 4 wherein the urging includes sealing portions of the front plates about the outer periphery of the pipe.
- 6. The method of claim 5 and peripherally pressing a first part of a front seal against the pipe while exposing the front seal to the pressure within the pressure chamber.
- 7. The method of claim 5 and peripherally pressing a second part of a front seal against the front plates while exposing the front seal to pressure within the pressure chamber.
Parent Case Info
This is a divisional of application Ser. No. 77,657, filed Sept. 21, 1979 now Pat. No. 4,277,231 issued July 7, 1981.
US Referenced Citations (13)
Divisions (1)
|
Number |
Date |
Country |
Parent |
77657 |
Sep 1979 |
|