JPH025507B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a lug for joining tubular frames constituting a bicycle, and in particular, when joining the lugs, while taking into account the aesthetic appearance of the bicycle, the joint part for brazing can also serve as a decorative hole. , relates to a method of performing brazing using a lug having a notched hole in the cylindrical side surface of the lug.

As is well known, in order to reduce the weight of bicycles, bicycles are constructed with tubular frames, and various types of lugs, such as head lugs and hanger lugs, are used to join the tubular frames. There are several other lags, but I will omit them here.

Referring to the attached drawings of typical head lugs, Figure 1 is for minicycles.
Figure 2 shows a commonly used regular car, but it has intaglio decorations on the surface, Figure 3 shows a car for women called ``Mitsukusuto'' or ``Bersoo,'' and Figure 4 shows a car for women. It is for bicycles called the "double top tube" type.

In FIGS. 1 to 4, the notched holes 10 which also serve as decorative holes of the present invention are bored in the side surface of a cylindrical body protruding from the tubular body of the lug body. This drilling method is performed by press cutting, and the holes are installed symmetrically on both sides of the cylindrical protrusion, as shown in Figures 5 and 12.
As shown in the cross-sectional view of the figure.

In a bicycle's tubular frame structure, the shape of the joint, which consists of one end of the tubular body and the cylindrical projection of the lug that engages with the tubular body, is a brazed joint because it is formed by inserting and fitting two tubes into each other. It is generally recognized that the shape is extremely good.

Regarding this, referring to FIG. 13, one end of the tube is inserted into and engaged with the cylindrical projection of the lug, and then the required brazing material is placed at the joining point shown at the tube end 11, and the brazing material is heated by a heating device. When heated, the gap between the tubes becomes wet and the brazing filler metal is sucked in by capillary action, cools and solidifies, forming a brazed joint that serves the desired purpose. This is a conventionally known brazing method.

As shown in the cross section of FIG. 12, the soldering method of the present invention involves drilling a notch hole 10 of an arbitrary shape in the cylindrical side wall on both sides of the lug, attaching a required brazing material to the notch hole 10, and Heat the brazing filler metal more,
Brazing is performed while drawing suction between the two tube walls using capillary action.

The notch holes 10 according to the present invention are installed symmetrically in the pipe walls on both sides as shown in FIG. 12, and the shape of the notch holes 10 is arbitrary as shown in FIGS. 6 to 11. Character shapes can also be used, and Japanese kana can also be applied.

The size of the notch hole 10 should be approximately 1/3 to 1/4 of the area of two notch holes 10 relative to the total side wall area of the cylindrical protrusion. If it is larger than this, the joint area between the pipes will be small and the joint strength will be weakened, and if it is smaller than this, the decorative effect will be significantly reduced.

Further, the size of the brazing material is the same as that of the notch hole, but is slightly larger than this so that it can be press-fitted into the notch hole and temporarily fixed.

FIG. 5 shows a bicycle hanger/lug 5 made of steel pipe. The hanger lug 5 supports the crankshaft of the bicycle pedal, supports the upright pipe and the lower pipe of the bicycle's tubular frame, and engages with a pair of chain stays. That is, as shown in the figure, it has four cylindrical projections.
In Fig. 5, the upper pair of protrusions 6 and 7 engage with a pair of chain stays, the central protrusion 8 engages with a vertical pipe (which is connected to the bicycle seat), and the lower protrusion 8 engages with a vertical pipe (which is connected to the bicycle seat). The protrusion 9 engages with the lower pipe, and the crankshaft of the pedal fits into the through hole indicated by the arrow.

In the hanger lug 5 having the above-described structure, in order to install the notch hole 10 which also serves as the decorative hole of the present invention, two notch holes are required at symmetrical positions in one cylindrical projection. , with four protrusions, the number is eight.

In FIG. 5, a pair of notch holes to be installed in the projection 9 for the lower pipe are omitted. The number of decorative holes/notches to be installed on the hanger/lug is arbitrary and depends on the user's request.

Recently, stainless steel pipes have been used as pipe materials for tubular frames for corrosion protection, and chromium-molybdenum steel pipes have been used for weight reduction.I believe that the decorative holes and cutout holes for brazing of the present invention can also be applied. The solder filler metal and flux are omitted in the present invention.

Furthermore, it is also possible to use a method in which known brazing materials and fluxes are used, and brazing is performed in a heating furnace under a required atmosphere.

Since it is possible to ship head lugs, hanger lugs, and other lugs with the brazing material still attached to the decorative hole/notch hole of the present invention, it is advantageous for frame manufacturers, and the brazing method can be improved. There is also the advantage of simplification.

[Brief explanation of drawings]

Figure 1 shows head lugs for minicycles, Figure 2
The figure shows a general head rug with a decorative intaglio pattern, Fig. 3 shows a mixed or versatile head rug with a decorative intaglio pattern, Fig. 4 shows a double top tube type head rug, and Fig. 5 shows a general head rug. hanger
The sketches of the lug, FIGS. 6 to 11 show various shapes of the decorative hole/notch hole, FIG. 12 is a sectional view of FIG. 13, and FIG. 13 shows a part of the side surface of the brazing. 1 to 4: various heads/rugs, 5: hangers/
Lug, 6, 7: Lug for chain stay, 8,
9: Lug for the vertical pipe and lower pipe, 10: Decorative hole and wax supply hole, 11: Connection point between the lug and one end of the pipe.

Claims (1)

[Claims] 1. For assembling a steel tube frame for a bicycle, a lug made of various steel pipes and provided with one or more tubular protrusions has an arbitrarily shaped notch hole occupying 1/3 to 1/4 of the cylindrical surface area of the protrusion. A brass solder of the same shape and slightly larger than the notch hole is installed in two places at symmetrical positions, and a flux consisting of a chemical substance that liquefies at a temperature lower than the soldering temperature or a reducing or non-oxidizing atmospheric gas is used. 1. A method of soldering a lug for a bicycle tubular frame, characterized in that brazing is performed using a heating device that generates a predetermined soldering temperature in a notch hole, and the notch hole is used as a decorative hole.