JPS6325853B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molding ring for bellows molding having a circular cross section, and more particularly to a molding ring consisting of a main molding ring divided in half and a pair of auxiliary rings.

A conventional bellows has a generally vertical cross section on its side, and has a smaller expansion/contraction ratio than a bellows with a circular side cross section.

Therefore, the object of the present invention is to form a bellows with a circular cross section that has a large expansion/contraction ratio.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bellows molding ring having a circular cross section according to the present invention will be described in detail below with reference to the accompanying drawings.

1 is a main molded ring divided in half, and one end is fitted onto the shaft 2 so that it can be opened and closed, and the other end has a flange 3.
and tighten it.

The main molded ring 1 has a T-shaped cross section, and the vertical piece 1
Grooves 5 into which a pair of auxiliary rings 4 to be described later are fitted are provided on both sides of a. The auxiliary ring 4 is formed with a vertical surface 4a abutted along the vertical piece 1a and an arcuate surface 4b protruding from the outer side of the lower part. The cross-sectional width of the arcuate surface 4b portion of the auxiliary ring 4 is equal to the central vertical piece 1a of the main forming ring 1.
The width is equal to or less than the cross-sectional width of.

Next, molded rings A consisting of the main molded ring 1 and a pair of auxiliary rings 4, 4 are arranged at equal intervals around the outer circumference of the blank pipe 7 fitted into the inner cylinder 6, and the main molded ring 1 is tightened with bolts 8. , further, by making the raw tube 7 and the inner cylinder 6 airtight, applying hydraulic pressure between them, and compressing them to a constant interval, the raw tube 7
The portion where the shape is contracted to form a trough, and the portion where the protruding arcuate surface 4b of the auxiliary ring 4 of the forming ring A forms the head portion of the blank tube 7 form a predetermined circular cross section by hydraulic pressure.

Next, the main molding ring 1 is untightened and opened around the shaft 2, and the auxiliary rings 4 are removed leaving the auxiliary rings 4 as they are. Next, the auxiliary rings 4, 4 are moved one by one into the removed gap of the vertical piece 1a of the main molding ring 1, and removed, and then the main molding ring 1 is closed and tightened to its original state, and the internal pressure is increased again in the same way as in the previous step. If the outer periphery of the head having a constant width of the blank tube 7 is compressed while applying pressure to the main molding ring 1, the inner diameter of the vertical piece 1a can be freely molded while preventing swelling due to internal pressure, resulting in a bellows with a circular cross section. By opening the main molding ring again after molding, a product with a high expansion/contraction ratio can be easily obtained. Further, although the above product has an arc-shaped valley, if the valley is desired to be a horizontal plane, it can be easily achieved by making the inner diameter surfaces of the auxiliary rings 4, 4 horizontal.

As mentioned above, the molded ring of the present invention has a horizontal piece, a vertical piece in the center, and a half-split main molded ring molded into a T-shaped cross section with grooves provided on both horizontal pieces of the vertical piece. It consists of a half-split auxiliary ring that fits into the grooves on both sides and protrudes outward from the plane and the bottom side of the vertical piece in contact with each other in an arc shape with a width equal to or narrower than the width of the vertical piece. , one end of the main molded ring is supported by a shaft, and the other end is provided with a flange that can be tightened.This product can easily form an arcuate cross section, and this product is different from the conventional vertical bellows with a side cross section. In addition, this molded ring can be easily punched out and molded without stretching the bellows after molding, and the arcuate protrusion of the auxiliary ring allows the bellows to have an accurate circular cross section. It has the effect of being moldable.

[Brief explanation of the drawing]

Figure 1 is a front view of the molded ring, Figure 2 is a side view of the molded ring installed in the raw pipe, Figure 3 is a partially enlarged side view when it is retracted, and Figure 4 is a partially enlarged view with the auxiliary ring removed. FIG. 5 is a partially enlarged side view of the bellows when molding is completed, and FIG. 6 is a side view of the bellows. DESCRIPTION OF SYMBOLS 1... Main forming ring, 1a... Vertical piece, 2... Shaft, 3... Flange, 4... Auxiliary ring, 4a... Vertical surface, 4b... Arc-shaped surface, 5... Groove, 6... Inner cylinder, 7... Base pipe, 8... bolt.

Claims (1)

[Claims] 1 The main body has a T-shaped cross section, and the inner surface of the horizontal piece has grooves on both sides of the vertical piece into which the upper ends of the auxiliary rings are fitted, and is split in half, with one end pivoted and the other end provided with tightening means so that it can be opened and closed. a molded ring, a flat surface that fits into said groove and abuts along both sides of the vertical piece, and an arcuate portion projecting outwardly on the lower side to a width equal to or less than the width of said vertical piece; A molding ring for bellows molding combined with a pair of half-split auxiliary rings.