Shield nozzle of gas shield arc-welding torch

Abstract

To provide a shield nozzle of a gas shield arc-welding torch in which screw processing is not necessary as attachment means of a copper pipe and a BS joint.SOLUTION: A shield nozzle of a gas shield arc-welding torch includes a contact tip 1 and a cylindrical copper pipe 4 wrapping the contact tip 1. In the copper pipe 4 of the gas shield arc-welding torch that jets shield gas to a welding part from a clearance between the copper pipe 4 and the contact tip 1, the copper pipe 4 is attached to a BS joint 3 to which the copper pipe 4 is attached detachably by inserting and press-fitting an attachment part of the copper pipe 4.SELECTED DRAWING: Figure 1

Description

Detailed Description of the Invention [Technical field]

[0001] The present invention relates to a shield nozzle for a gas-shielded arc welding torch used when performing gas-shielded arc welding. [Background technology]

[0002] Generally, a welding torch used in gas shielded arc welding such as MAG welding or MIG welding is composed of a roughly bullet-shaped contact tip from which a solid wire is fed, a cylindrical tip holder which holds the base of the contact tip, a tubular pipe arranged to enclose the contact tip and the tip holder, and an insulator to which the pipe and tip holder can be attached.

[0003] Gas-shielded arc welding is a welding method in which a large current is passed through a contact tip to a solid wire that is continuously fed out, generating an arc between the solid wire and the workpiece, and the heat generated melts the solid wire and the workpiece to weld the workpiece. When welding, in order to prevent the occurrence of blowholes due to contact between the welding point and oxygen, an inert gas such as CO2 or argon is supplied from a gas supply port formed in the tip holder, and the inert gas is supplied to the welding point from the tip of a pipe to prevent contact between the welding point and oxygen. The pipe is indispensable for gas-shielded arc welding, as it prevents the diffusion of the inert gas and reliably supplies the inert gas to the welding point.

[0004] Conventionally, the shield nozzle described in Patent Document 1 is detachably attached by threading a threaded portion 101 on the inner surface of the base end of a cylindrical pipe 100 as shown in FIG. 4, and threading a threaded portion 201 on the outer surface of an insulator 200 as shown in FIG. 5, and screwing the pipe 100 to the insulator 200.

[0005] Moreover, the shield nozzle described in Patent Document 2 is detachably attached by engaging an attachment portion 102 at the base end of a copper pipe 100 with a joint 200 that is detachably attached to a welding torch as shown in FIG. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Utility model registration No. 3158626 [Patent Document 2] JP 2018-144102 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the shield nozzle described in Patent Document 1, a threaded portion was cut on the entire inner surface of a cylindrical pipe using a lathe or the like. This required skilled machining and was time-consuming, making the shield nozzle expensive.

[0008] Furthermore, the insulator must be removed when removing spatter that has adhered during welding, which poses the problem of time-consuming replacement work.

[0009] In order to solve such problems, the shield nozzle described in Patent Document 2 has a joint instead of an insulator, so that only the copper pipe can be attached and detached from the joint. Since the attachment is performed by pressing the mounting portion of the base end of the copper pipe into the joint, there is no need to thread the inner peripheral surface of the copper pipe, making the processing of the shield nozzle easy and inexpensive; furthermore, when removing spatter that has adhered during welding, it is only necessary to replace the copper pipe without replacing the joint, which has the effect of facilitating the replacement work.

[0010] However, the joints of this invention are made of plastics such as polyacetal resin (POM), fluororesin, and polyether ether ketone resin (PEEK), and are therefore vulnerable to heat. There was a problem in that the joints would melt during welding, making it necessary to replace the joints themselves.

[0011] The present invention has been made to eliminate the drawbacks of the above-mentioned conventional inventions, and aims to provide a shield nozzle that is easy to process, inexpensive, easy to replace, and long-lasting. [Means for solving the problem]

[0012] The present invention, made to achieve the above-mentioned object, is a shield nozzle for a gas-shielded arc welding torch which includes a contact tip and a cylindrical copper pipe that encases the contact tip, and which sprays shielding gas onto a weld from a gap between the copper pipe and the contact tip, and is characterized in that the copper pipe is attached by inserting and pressing an attachment portion of the copper pipe into a BS joint which detachably attaches the copper pipe.

[0013] It is also preferable that the outer periphery of the tip of the copper pipe in the insertion direction, which is the mounting portion, is tapered. Effect of the Invention

[0014] According to the present invention configured as described above, the attachment means between the copper pipe and the BS joint does not require threading and can be easily manufactured. Furthermore, when replacing the copper pipe, it is necessary to replace only the copper pipe without replacing the BS joint, which has the effect of facilitating the replacement work.

[0015] In addition, because the BS joint is made of brass, it will not melt due to Joule heat during welding, making it possible to provide a long-lasting joint.

[0016] Furthermore, by tapering the outer periphery of the tip of the copper pipe in the insertion direction, the installation work can be facilitated. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a partial cross-sectional view of a shield nozzle showing an embodiment of the present invention. [Diagram 2] FIG. 2 is a partial cross-sectional view showing the copper pipe and the BS joint of the embodiment in a separated state. [Diagram 3] FIG. 2 is a partial cross-sectional view showing a copper pipe according to an embodiment of the present invention press-fitted into a BS joint. [Figure 4] FIG. 11 is a partial cross-sectional view showing a conventional shield nozzle. [Diagram 5] FIG. 11 is a partial cross-sectional view showing an example of a conventional shield nozzle. [Figure 6] FIG. 11 is a partial cross-sectional view showing another example of a conventional shield nozzle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] First, an embodiment of the present invention shown in FIGS. 1 to 3 will be described. Reference numeral 1 denotes a contact tip, which is detachably attached by screwing onto the tip of a tip holder 2. The contact tip 1 and tip holder 2 are made of copper or a copper alloy, which has excellent electrical conductivity. A through hole is provided at the center of the tip of the contact tip 1 to feed out the welding wire fed into the tip holder 2.

[0019] Reference numeral 3 denotes a substantially cylindrical BS joint, that is, a joint made of brass. The BS joint 3 is attached to the tip holder 2 by screwing a female thread 3a, which is threaded on the inner peripheral surface at the base end, into a male thread 2a, which is threaded on the outer peripheral surface at the base end of the tip holder 2.

[0020] Reference numeral 4 denotes a copper pipe having a substantially cylindrical shape, which is detachably attached to the BS joint 3. That is, the copper pipe 4 is attached by inserting the tip side of the BS joint 3 into the inner side. In this case, the copper pipe 4 is attached with its tip surface 41 abutting against the side surface of a step 31 protruding from the inner peripheral surface of the BS joint 3, and is held in an appropriate attachment position.

[0021] The copper pipe 4 has an outer diameter smaller than the inner diameter of the BS joint 3, and the outer periphery of the end in the insertion direction, which serves as the mounting portion, is tapered 4a. This makes it easy to insert the pipe into the BS joint 3, and the O-ring 5 fitted into the groove 32 formed around the entire circumference of the inner surface of the BS joint 3 can be pressed in while being pressed, making the mounting process easy. The O-ring 5 is made of fluororubber, i.e., type 4D, and has elasticity and heat resistance.

[0022] In the illustrated example, the tapered shape 4a on the outer periphery of the tip in the insertion direction of the copper pipe 4 is chamfered to have an outer arc surface, but it may be tapered. Furthermore, by forming the tapered shape 4a on both ends of the copper pipe 4, the insertion direction of the attachment part can be in either direction, which improves the efficiency of the insertion work.

[0023] The inner surface of the tip of the BS joint 3 is chamfered 33, which serves as a guide when inserting the copper pipe 4 into the BS joint 3, making the insertion operation easier.

[0024] In addition, a plurality of gas supply ports 21 are formed in the center of the tip holder 2. The gas supply ports 21 are used to supply shielding gas such as carbon dioxide gas, or a mixture of argon gas and carbon dioxide gas or oxygen gas. The shielding gas is supplied from between the tip holder 2 and the copper pipe 4 to the welding point at the tip of the copper pipe 4.

[0025] Next, a method for attaching and detaching the copper pipe 4 to the BS joint 3 in the above embodiment will be described.

[0026] First, the O-ring 5 is fitted so that the inside is exposed in the concave groove 32 formed around the entire circumference on the inner surface of the BS joint 3. Then, the BS joint 3 is attached to the tip holder 2 by screwing the female thread 3a, which is threaded on the inner peripheral surface on the base end side, into the male thread 2a, which is threaded on the outer peripheral surface on the base end side of the tip holder 2.

[0027] Then, the copper pipe 4 is inserted into the inner surface of the BS joint 3 from the tip side, which is the mounting portion, and attached by abutting the tip surface against the step 31 protruding from the inner peripheral surface of the BS joint 3. In this case, the copper pipe 4 has an outer diameter smaller than the inner diameter of the joint nozzle 3, and the tip outer periphery in the insertion direction has a tapered shape 4a, so that the insertion work into the BS joint 3 is easy, and the inside of the O-ring 5 fitted into the concave groove 32 formed around the entire circumference on the inner surface of the BS joint 3 can be pressed in against its elasticity, making the installation work easy.

[0028] When the copper pipe 4 is attached to the BS joint 3, if the copper pipe is pulled out, it will come off from the BS joint 3 against the elasticity of the O-ring 5, and the copper pipe 4 can be replaced.

[0029] As described above, according to the present invention, the copper pipe 4 is detachably attached to the BS joint 3 by pressing the mounting portion at the base end into the BS joint 3. This eliminates the need to thread the copper pipe 4, and allows the shield nozzle to be manufactured easily and inexpensively. [Explanation of symbols]

[0030] 1: Contact tip 2: Tip holder 2a: Male thread 3: BS joint 3a: Female thread 31:Dan section 32: Concave groove part 4: Copper pipe 4a: Tapered shape 41: Tip surface 5: O-ring

Claims

1. A shield nozzle for a gas-shielded arc welding torch, comprising a contact tip and a cylindrical copper pipe that encases the contact tip, and in which shielding gas is sprayed onto a weld from a gap between the copper pipe and the contact tip, the copper pipe of the gas-shielded arc welding torch is attached by inserting and press-fitting an attachment portion of the copper pipe into a BS joint that detachably attaches the copper pipe.

2. 2. The shield nozzle of a gas shielded arc welding torch according to claim 1, wherein a tip outer periphery of the copper pipe in the insertion direction, which is a mounting portion of the copper pipe, is tapered.

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