JPH0355643Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a shovel used in coal mines and other places where explosive gas is present.

(Prior Art) When an ordinary steel shovel is used in a coal mine or other place filled with explosive gas, there is a risk of an explosion caused by sparks generated when it comes into contact with stones, etc. Therefore, safety shovels made of beryllium-copper alloy, which do not cause sparks, have been used in places where there is a risk of explosion. This type of shovel is made by press-forming a rolled plate of beryllium copper alloy into the shape of the shovel body, solution-treated and hardened, and attached to the wooden handle by pressing. When attaching the handle, cracks may occur in the handle attachment part and its surrounding areas, and even if no cracks occur during manufacture, these parts are susceptible to brittle fracture during use.

(Problems to be solved by the invention) The present invention solves the conventional problems as mentioned above, and can be used safely even in places where there is a danger of explosion. It was completed with the aim of creating a shovel that would not cause any cracks at the handle connection part, etc.

(Means for Solving the Problems) The present invention provides an annealing structure for the handle connection portion of a shovel body made of beryllium copper, which is formed by press forming and has a hardened structure, and also has a hardened structure. The handle is connected to the handle connection part in a crimped state.

(Embodiment) Next, the present invention will be explained in detail with reference to the illustrated embodiment. 1 is a shovel body made of beryllium copper;
is the handle connection part, and 3 is the wooden handle. Most of the shovel body 1 has a hardened structure that has been subjected to age hardening treatment, but only the handle connection part 2 and its surrounding area has an annealed structure.

To manufacture such a shovel body 1, for example, a rolled plate of beryllium copper with a thickness of 1.8 mm is punched out using a press, press-formed into the shape shown in the figure, and subjected to solution treatment to give the shape. After correction, hardening treatment is performed by heat treatment in sand. Then, insert only the handle connection part 2 into the furnace and heat it at 750°C for 3 to 30 minutes.
When the partial annealing process is performed for about 4 minutes, the hardened structure of the handle connection part 2 and its surrounding area changes to an annealed structure. If the tip of the handle 3 is inserted and pressed into the handle connection part 2 which has been softened by annealing and has regained its cold workability, the handle connection part 2 will be accurately deformed to follow the shape of the handle 3. The handle 3 is held securely, and unlike when hardened tissue is pressed, no cracks occur. Note that 4 is a rivet driven in to securely fix the handle 3.

(Function) A shovel constructed in this way can be used in the same way as a normal shovel, but since the shovel body 1 of the present invention is made of beryllium copper, it may not be exposed to rocks, stones, etc. during use. It does not produce sparks even if it comes into contact with Therefore, the shovel of the present invention can be used safely even in places such as coal mines, which are filled with flammable gases that pose a risk of explosion. Furthermore, since the shovel of the present invention has an annealed structure for the handle connection part 2 of the shovel body 1, even when the handle 3 is connected by press working, there will be no cracks in the handle connection part 2 or its surrounding areas. These parts will not undergo brittle fracture during use. It should be noted that since the annealed structure is applied only to the portions that are not directly related to the function of the shovel, there is no problem with workability.

(Effects of the invention) As is clear from the above explanation, the present invention can be used safely without the risk of sparks even in places where there is a danger of explosion, such as inside a coal mine. There is no risk of cracks occurring during use. Therefore, the present invention has extremely great practical value as a shovel that solves the conventional problems.

[Brief explanation of drawings]

The drawing is a perspective view showing an embodiment of the present invention. 1... Shovel body, 2... Handle connection part, 3...
Pattern.

Claims (1)

[Scope of utility model registration request] The handle connection part 2 of the shovel body 1 made of beryllium copper, which is formed by press forming and has a hardened structure, is made into an annealed structure, and the handle 3 is crimped to the handle connection part 2 which has this annealed structure. A shovel characterized by being connected.