JPS61253134A - Manufacture of seat lug with collar pedestal - Google Patents

Abstract

PURPOSE:To attain a simplification of manufacture and cost down for a seat lug with a collar pedestal by forming a swelled out projection by performing a hydraulic bulge forming, and thereafter obtaining a final product by performing a secondary work at a projection forming a pedestal. CONSTITUTION:A metallic raw material tube is inserted to a segmental die provided with recessed part corresponding to projections 3, 4 to be bulged out and thereby a raw material tube 2 having the desired projections 3, 4 is obtained by means of a hydraulic forming. At the secondary working, the end of the projection 3 is finished to an opening 3a with a special form, and after the end of the projection 4 is finished to a pedestal 4a, an upright cylinder 5 is fixed to the pedestal 4a by welding. And the pedestal 4a with the cylinder 5 fixed, is slitted to form both ears 7a, 7b. In consequence, the simplification of the manufacture and the cost down for the seat lug with a collar pedestal for an automobile is made feasible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seat lug located directly below the saddle of a bicycle, and more particularly to a method of manufacturing a seat lug with a base for a binaural clamping part called a collar.

Bicycle seat lugs are located directly under the bicycle saddle and have the function of freely adjusting the height of the saddle. Conventionally, the typical manufacturing method for seat lugs is to cut a flat metal plate into the required shape. Then, this is formed into a cylindrical shape through operations such as press working, and a small cylinder with concave sides called a double-eared pin tightening part, or collar, for adjusting the saddle height is made.

It is fixed to the side surface of the cylindrical body of the seat lug using brazing, welding, etc., and the final process consists of cutting this small cylinder together with the seat lug body into slits to create both ears.

The above-mentioned small cylinders with concave sides are commercially available.

Since it is made from a small cylindrical material, its cost is higher than that of a straight cylinder.

The present invention provides a pedestal that allows the use of a right cylinder without using this expensive concave side cylinder.
The lug is designed to be installed on the side of the cylinder.

Therefore, a material tube that can be used for seat lugs is used as a starting material, and a hydraulic bulge forming method is applied to this material to provide a new method for producing seat lugs.

The invention will now be described with reference to the accompanying drawings.

Mechanical structure steel pipe 5TKfV11 specified by JIS as material pipe
Choose 1A - as an example its size is 31.8mm outside diameter
.

The thickness of the tube wall is 1.6 to 2 mm, and the length is 100 strokes.

Such a material tube 1 (FIG. 1) is subjected to hydraulic bulge forming. Hydraulic bulge forming method is Japanese patent 417728, 418
055.480529.482147.730010, etc., and its introduction and implementation progressed widely in the bicycle industry, and the applicant's predecessor also obtained Japanese Patent No. 982106 entitled "Method for manufacturing decorative head lugs for bicycles." 91 This application is constructed with reference to these patents.

According to the patent, a raw material tube is placed into a split mold that can carve the required number of bulging protrusions, high-pressure hydraulic oil is introduced into the pipe, and this action forms the required bulging protrusions on the outer surface of the tube. In the present invention, one protrusion is formed on each side of the tube axis.

Referring to the drawings of the above-mentioned patents and describing the forming method of the present application, the concept of the hydraulic bulge forming machine is that of an arch-shaped frame structure as shown in Fig. 4. A hydraulic vertical movement ram 17 is suspended, the ram 17 has an upper die 20 for split molds attached, a lower die 20a is installed on the bed 21, and horizontal movement rams 18 and 19 are installed, and the split mold for charging one material tube is installed. 20.20a is fixed on the ped 21 by three rams 17, 18, and 19, and the pressurized hydraulic oil 11 is subjected to high pressure of 950 to 1200 kg/aM to form a bulge from inside the pipe, and the upper limit of this oil pressure is Recently, it has become possible to produce up to 1500 kg/cJ.

In FIG. 3, the split mold 20 is provided with an indentation Z in which a relatively small protrusion 4 and a relatively large protrusion 3 can bulge out, and the large protrusion 3 and the small protrusion 4 are formed on the outer surface of the material tube 2 by bulge forming.
The external shape with the bulging part is the same as shown in FIG.

An outline of the hydraulic circuit shown in Fig. 3 will be described. A piston 1 is inserted into the inside of the material tube 2 charged into the split mold 20 by an oil supply pump 13.
The hydraulic oil 11 is filled through the oil introduction hole passing through the center of the pipe 5.15a, both ends of the material tube 2 are tightly sealed by the piston 15.15a, and when the oil pressure rises as described above due to the action of the high-pressure pump 14, the oil pressure increases. Bulge forming is performed, and the required bulging protrusions 3 and 4 are formed as shown in FIG.

Incidentally, the material tube 1 is simply a starting material, and the material tube 2 refers to a material having a bulging protrusion or a material in the process of being molded.

Material pipe 2 shown in Fig. 2 obtained by applying the hydraulic bulge forming method
has bulges 3 and 4.

The protrusion 3 is opened and subjected to further secondary processing to create a specially shaped opening 3a according to the needs as shown in the side view of Fig. 5. When this opening 3a is viewed from above, it is shown in Fig. 6. As shown, the tip of the opening 3a is sharp and has a protrusion 4.
In the side view of Figure 5, the shape of a is entirely concave in an arc shape.

In FIG. 6 viewed from above, it is the cylindrical wall of the material tube 2.

An example of the size of the material tube 1 is the above-mentioned through hole, but the size after bulging is approximately as follows: Material tube 2 (Fig. 2) Outer diameter: 32 mm (approximately) Tube wall thickness: 1 .8~2.3nm+(・) length
50mff1 (l) In FIG. 5, a seat post (not shown) for supporting the saddle passes through the seat lug through the upper opening 2a and the lower opening 2b.

The bulging projection 4 shown in FIG. 2 and the bulging projection 4a shown in FIGS. 5 and 6 serve as a base for supporting the collar in the present invention, and as shown in FIG. 7, the bulging projection 4a shown in FIGS. The pedestal 4a has the shape of a semi-cylindrical recessed in the outer wall, and is integrally formed with the seat/lug main body by hydraulic bulge forming method, and furthermore, by secondary processing, the side wall of the right cylinder 5 shown in Fig. 8 is formed. Accurately contact and apply the right cylinder 5 to the pedestal 4a for joining by brazing, welding, etc., and firmly fix it with υ.

FIG. 10 is a side view showing the state in which the right cylinder 5 is fixed to the pedestal 4a, and FIG. 11 is a perspective view showing the state in which the right cylinder 5 is fixed to the pedestal 4a more clearly.

FIG. 12 shows that when the seat/lug with a pedestal of the present invention is assembled into a bicycle, slits are provided for both ears 7a.

7b is made.

As described in detail above, according to the present invention, a seat lug can be obtained in one step by using a metal pipe as a starting material and provided with a desired shape and a collar pedestal by the hydraulic bulge forming method. This is a remarkable invention in the bicycle parts industry, where it is processed into a final product.

[Brief explanation of the drawing]

The drawings illustrate the present invention: Fig. 1 shows a raw material pipe as a starting material, Fig. 2 shows a second material pipe obtained by hydraulic bulge forming, and Fig. 3 shows a hydraulic circuit included in the hydraulic bulge forming method. Fig. 4 is an overview of the hydraulic bulge forming press machine, Fig. 5 is a side view of the secondary material pipe subjected to secondary processing, Fig. 6 is a view of Fig. 5 viewed from above, Figure 7 is a perspective view of Figure 5. Figure 8 is a right cylindrical tube, Figure 9 is a cylindrical tube with a recess, Figure 10 is a side view of Figure 7 and Figure 8 combined, and Figure 11. is the 10th
The perspective view of the figure, FIG. 12, is a completed product of the seat and lugs that are incorporated into the bicycle. 1・・・・・・・・・・・・・・・・・・Material tube 2・・
・・・・・・・・・・・・・・・Pipe material with projections 3, 4 3.4・・・・・・・・・Bulging projections 3a, 4a
・・・・・・Secondary processing protrusion 5・・・・・・・・・・・・
・・・・・・Right cylindrical tube 6・・・・・・・・・・・・・・・
・・・・・・Concave Hatsukata pipes 7a, 7b・・・Both ears 11・・・・・・・・・・・・Hydraulic oil 12, 12
a... Cylinder 13...... Oil pump 14.
・・・・・・・・・・・・High pressure pump 15, 15a
···piston

Claims (1)

[Claims] A material tube of a predetermined size is inserted into a split mold with grooves corresponding to the bulging protrusion that engages with the bicycle's upper pipe and the bulging protrusion that becomes the collar pedestal, and the mold is heated by hydraulic pressure. Set it in the bulge forming machine and perform the hydraulic bulge forming process to obtain 2.
Opening the upper pipe-engaging bulging protrusion on each of the material tubes with bulging protrusions, performing secondary processing to obtain the desired shape,
The collar pedestal bulging protrusion is subjected to secondary processing so that it becomes a concave semi-cylindrical collar pedestal without an opening, and a half side of the right cylindrical piece is fixed to the concave semi-cylindrical pedestal, and the pedestal is attached. A method for producing a seat/lug with a collared pedestal for a bicycle, characterized by cutting slits in a right cylinder and the seat/lug body to make a seat/lug with a collared pedestal.