JPH075026B2 - Fuel tank manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a fuel tank of a portable engine such as a brush cutter.

Conventionally, this type of fuel tank was made of a synthetic resin film and was mounted below the engine, so when the engine is placed on the ground, it will come into contact with the bottom surface of the fuel tank. The bottom surface is prone to damage such as cracks. For this reason, legs for contacting the ground are separately manufactured and fixed to the bottom surface, which complicates the structure and increases the number of manufacturing processes. It was a hindrance to efficiency.

Further, conventionally, in a fuel tank made of synthetic resin, since a thermoplastic powdery synthetic resin film is filled in a mold and heat-molded, it is difficult to mold a hollow body, and thus it is difficult to mold a hollow body. Shaped shells were molded and glued together to form a hollow body. For this reason, the work efficiency is poor and the cost is high, and it is not suitable as a fuel tank for a small engine. In response to this drawback, there was a method of manufacturing a fuel tank by blow molding, but with this method, the entire surface of the tank is uniform and the bottom surface in contact with the ground is easily damaged. When placed on the ground, it could not be used, that is, in this method, the tubular heat-welding cloth-like synthetic resin film was flattened into two layers, and the upper and lower layers were preheated. It is sandwiched between the upper and lower molds that have hollow molds inside, the edges are crimped, air is pressed between the upper and lower membranes, and the membranes are pressed against the inner surface of the hollow molds. It is cooled, solidified and molded. In this case, since the entire circumference of the tank is formed of the same tubular material, the entire circumference has the same wall thickness.

According to the present invention, the lower side of the synthetic resin film is pressure-bonded to the reinforcing plate made of synthetic resin, which is preheated and inserted, at the portion corresponding to the bottom surface of the fuel tank of the hollow mold portion, so that the fuel tank is grounded. It is intended to easily manufacture a fuel tank whose bottom surface is not damaged even when mounted on the.

The present invention will be described in detail below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a brush cutter, which connects a bearing body 5 that rotatably supports a rotary blade 3 and an engine 7 with a connecting rod 9. 11 is a handle fixed to the connecting rod 9, 13 is a hanger suspended from the connecting rod 9 and the engine 7, and a shoulder strap 15 is connected thereto. 17 is a fuel tank mounted below the engine 7, 19 is a fuel tank 17
It is the cap of the inlet 21 of.

Reference numerals 23 and 25 denote an upper mold and a lower mold each having a hollow mold portion 27 having a shape corresponding to the outer shape of the fuel tank 17, and are divided by a dividing surface 29 including the center line of the injection port 21. Reference numeral 31 is an injection needle that is inserted into the position of the dividing surface, and communicates with the air tube 33 to inject air. Reference numerals 35 and 37 are an upper film and a lower film obtained by flattening a cloth-shaped synthetic resin film formed in a tubular shape. Reference numeral 39 is a reinforcing plate, which is obtained by cutting the tubular synthetic resin film to an appropriate length and is flatly doubled.

In the above embodiments, the brush cutter 1 hangs the shoulder strap 15 on the operator's shoulder, grips the handle 11 with both hands, and uses the rotary blade 3 that is rotated by the drive of the engine 7 to brush grass or the like on the ground. It is something to do. When the brush cutter 1 is placed on the ground, the position of the connecting rod 9 close to the rotary blade 3 is supported by a stand (not shown), and the engine 7 is placed with the bottom surface of the fuel tank 17 in contact with the ground. In molding the fuel tank 17, the reinforcing plate 39 made of a preheated synthetic resin film is inserted into the hollow mold part 27 of the lower mold 25 at a position corresponding to the bottom surface of the fuel tank 17, and then, The preheated synthetic resin films 35, 37 are placed between the upper mold 23 and the lower mold 25 at the position of the dividing surface 29, and the edges are crimped and clamped, and the synthetic resin films 35, 3 by the injection needle 31.
When air is pressed in between 7, the synthetic resin films 35 and 37 are hollow.
It is pressed against the inner surface of 27, cooled, solidified and molded. The upper mold 23 and the lower mold 25 are separated to take out the molded product inside, and the reinforcing plate 39 is pressure-bonded to the synthetic resin film 37, so that the bottom surface of the fuel tank 17 can be thickly provided. .

Since the present invention is the method for manufacturing a fuel tank as set forth in the claims, it is possible to form a large thickness dimension of the bottom surface in contact with the ground, and further, the manufacturing is facilitated, and the work efficiency of fuel tank manufacturing is improved. It can be improved.

It should be noted that the present invention is not limited to the above-described embodiments, but can be implemented in other modes. Also,
Reference numerals in the claims do not limit the technical scope of the present invention.

[Brief description of drawings]

FIG. 1 is a perspective view of a brush cutter, and FIG. 2 is a side sectional view of an embodiment of the present invention. (Explanation of the symbols indicating the main parts of the drawing) 23 …… Upper mold, 25 …… Lower mold 27 …… Hollow mold, 35,37 …… Synthetic resin film 39 …… Reinforcement plate

Claims (1)

[Claims] 1. A method of manufacturing a fuel tank, which is mounted below a portable engine such as a brush cutter, has a substantially flat bottom surface, and the bottom surface comes into contact with the ground when placed on the ground. The combined cloth-like synthetic resin films 35, 37 are preheated, and the edges are crimped and clamped by the upper and lower molds 23, 25 forming the hollow mold portion 27 inside, and the upper and lower synthetic resin films 35, 37 are held. While pressurizing air between to form a shape corresponding to the hollow mold portion 27, only the portion of the hollow portion 27 corresponding to the bottom surface of the fuel tank, preheated and inserted synthetic resin film 35. A method of manufacturing a fuel tank, characterized in that the lower synthetic resin film 37 is pressure-bonded to a reinforcing plate 39 made of the same type of synthetic resin as 35 and 37.