JPH01175809U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of this device, FIGS. 2 a and b are diagrams showing the operation of this device, and FIG.
The figure shows a conventional backflow prevention device. DESCRIPTION OF SYMBOLS 1...Screw body, 2...Osaegane, 3...Stopper ring, 4...Sleeve, 5...Holding part, 6...
Ring, 7...Resin passage hole, 8...Valve seat, 9
...Mounting hole, 10...Guide hole, 11...Valve stem, 12...
Pressure receiving surface, 13...valve part, 14...spring, 15...
Nut, 16...Resin passage, 17...Cylinder, 18
...Seal surface, 19...Ratsupa-shaped seal surface.

Claims (1)

[Claims for Utility Model Registration] 1. In a backflow prevention device having a screw head coupled to the tip of the screw body 1 and a backflow prevention ring that does not rotate in conjunction with the screw head, the backflow prevention ring includes: A resin passage hole 7 communicating from the side (screw main body side) to the front side (nozzle side) is formed, and a valve for opening and closing the resin passage hole 7 is provided through the center of the screw head. The valve is equipped with a spring 14 that urges the valve in a direction to close the resin passage hole 7, and a pressure receiving surface 12 is formed in the front of the valve portion 13, so that the valve is closed by resin pressure during plasticization. A backflow prevention device for an injection molding machine characterized by being opened. 2. In a backflow prevention device having a screw head coupled to the tip of the screw body 1 and a backflow prevention ring that does not rotate in conjunction with the screw head, the screw head has a stopper ring 3 in the mounting hole 9 at the tip of the screw body 1. The backflow prevention ring is connected to the valve seat 8 by screwing the sleeve 4 between the sleeve 4 and the sleeve 4.
The valve seat 8 is connected to the front side (nozzle side) of the ring 6 by screwing or the like, and the valve seat 8 is connected to the center part of the backflow prevention ring at the rear side. side(
A resin passage hole 7 is formed which communicates with the front side (nozzle side) from the screw body side), and a valve is provided that penetrates the center of the screw head to open and close the resin passage hole 7. is the front from the mounting hole 9 side of the screw main body 1 (nozzle side)
The valve stem 11 is slidably fitted into the guide hole 10 of the face gun 2 which penetrates through the valve stem 11, and the front end of the valve stem 11 has a hemispherical shape in which the front flat part becomes the pressure receiving surface 12 and the rear spherical surface becomes the sealing surface 18. In addition, the valve seat 8 is provided with a flap-shaped sealing surface 19 so that the sealing surface 18 of the valve stem 11 closes the resin passage hole 7 at the rear portion thereof protruding into the mounting hole 9. The resin passage 1 is provided with a spring 14 which is biased in the direction of being pressed against the screw head, and the valve is opened by the resin pressure during plasticization to create a resin passage 1 between the outside of the screw head and the inside of the backflow prevention ring.
A stopper ring 3 is provided on the screw head to form a retaining portion 5 of the backflow prevention ring.
A backflow prevention device for an injection molding machine, characterized in that the backflow prevention device is configured to be in contact with and held in the injection molding machine. 3 The spring 14 is fitted into the portion of the valve stem 11 that protrudes into the mounting hole 9, and
3. The backflow prevention device for an injection molding machine according to claim 2, wherein a nut 15 is screwed into the threaded portion at the rear end.