JP3448984B2 - Spray gun for painting - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray gun for spraying paint at a relatively low pressure, such as an air spray gun, and more particularly to switching between spraying and stopping paint. The present invention relates to a spray gun for painting with an improved on-off valve. 2. Description of the Related Art Conventionally, in a spray gun for spraying paint at a relatively low pressure, such as an air spray gun, the paint is spread around a valve rod of an on-off valve for switching between spraying and stopping the paint. In order to prevent leakage to the rear side of the gun body with the drive unit, a sealing material such as V packing was inserted from the rear side of the gun body and tightened with screws.
When the seal material is worn due to friction with the valve rod, it is necessary to disassemble the gun body and replace the seal material. [0003] For this reason, there is a problem that it takes time to replace the seal material, and that the paint leaks out and stains the worker and the surroundings. [0004] Problems to be solved by the present invention are that it takes time to replace the sealing material, and that the paint leaks out and soils the worker and the surroundings. [0005] The spray gun for coating according to the present invention, as a means for solving such a problem, includes a female screw formed at a distal end portion of a gun main body from a distal end side of the gun main body. A male screw thread is formed, and a valve seat body is fitted in a valve hole formed in the center, and a female screw formed on the inner periphery of the valve seat body. A seal body in which a sealing material that is in close contact with the valve rod is fitted into a central hole through which the driven valve rod is inserted, and a communication hole that communicates a paint passage formed in the gun body with a valve chamber formed in the valve seat body. And an on-off valve unit consisting of According to the present invention, the opening / closing valve unit in which the valve seat body and the seal body are integrated by screws is screwed in from the distal end side of the gun body, and the gun body is disassembled. The valve seat body and the seal body can be removed from the front end side of the valve seat, and the seal body is removed from the valve seat body, and the seal body fitted with a new sealing material is assembled to the valve seat body to form an on-off valve. Since the sealing material can be replaced by screwing the unit into the gun body, there is an effect that the replacement of the sealing material can be performed in a short time without polluting the surroundings. An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a gun body, which has a device hole 2 having a circular cross section in which a female screw 3 is formed near an entrance of the gun body. Reference numeral 4 denotes an on-off valve unit according to the present invention, which is roughly classified into a valve seat body 5 made of stainless steel and a seal body 6 made of synthetic resin. The valve seat body 5 comprises a hexagonal head 7 and a cylindrical portion 8, and a male screw 9 for screwing with the female screw 3 is formed on the outer periphery of the cylindrical portion 8. A valve hole 10 communicating with the hollow of 8 is formed, and a valve seat 11 is fitted to the cylinder portion 8 side. The seal body 6 includes a large-diameter portion 12 that fits tightly into the device hole 2 and a small-diameter portion 13 that fits into the cylindrical portion 8 of the valve seat body 5. A male screw 15 screwed with a female screw 14 formed on the inner periphery of the tube portion 8 is formed. Further, the outer periphery of the distal end portion of the small-diameter portion 13 is fitted into a concave portion 16 formed at a deep end of the inner periphery of the tube portion 8. A projection 17 is formed so that the inner space of the small-diameter portion 13 becomes a valve chamber 31.
A sealing member 18 made of U packing which is in close contact with the valve rod 19 is fitted to the rear end thereof, and an L packing 21 which is in close contact with the valve rod 19 is fitted in a device hole 25 at the rear end of the large diameter portion 12. A spacer 24, an O-ring 23, and a stopper 24 for pressing the L packing 21 through the O-ring 23 are fitted. The stopper 24 fits a projection 27 into a concave portion 26 formed in the device hole 25 and escapes. It is fixed to impossible,
An O-ring 28 is fitted around the outer periphery of the large diameter portion 12. An annular gap 29 is formed between the distal end of the cylindrical portion 8 of the valve seat body 5 and the step portion 13 of the large diameter portion 12 and the small diameter portion 13 of the seal body 6. A communication hole 30 that communicates with the valve chamber 31 is formed in a portion corresponding to. The gap 29 matches the paint passage 32 formed in the gun body 1. The opening / closing valve unit 4 of the present invention has the above-described structure. When the valve rod 19 is retracted by a driving source (not shown), the valve element 20 fixed to the distal end is separated from the valve seat 11 and the valve hole 10 is opened to open the paint. From the passage 32 to the gap 29 and the communication hole 30
When the paint that has passed through the valve chamber 31 is discharged from the valve hole 10, the valve rod 19 returns and the valve body 20 hits the valve seat 11, the valve hole 10 closes and the discharge of the paint stops. When the seal member 18 is worn due to friction with the valve rod 19, the valve seat body 5 is rotated by applying a tool to the head 7 and the female screw 3 and the male screw 9 are screwed together. Is pulled out of the device hole 2 together with the seal body 6. When the valve seat body 5 and the seal body 6 are relatively rotated, the female screw 14 and the male screw 15 are screwed together.
The valve seat body 5 and the seal body 6 are separated. Therefore, the seal body 6 fitted with the worn seal material 18 is discarded, and the seal body 6 fitted with the new seal material 18 is connected to the valve seat body 5 by screwing the female screw 14 and the male screw 15 to open / close the valve unit. The on-off valve unit 4 is mounted on the gun body 1 by screwing the female screw 3 and the male screw 9 together. The fitting between the projection 17 at the tip of the small diameter portion 13 of the seal body 6 and the recess 16 of the cylindrical portion 8 of the valve seat body 5 is performed so that the seal body 6 and the valve seat body 5 are not inadvertently separated. When the seal body 6 and the valve seat body 5 are forcibly rotated relative to each other, the small-diameter portion 13 is elastically fitted and fitted, and the fitting is released.

[Brief description of the drawings] FIG. 1 is a sectional view of one embodiment of the present invention. [Explanation of symbols] 1: Gun body 3: Female screw 4: On-off valve unit 5: Valve seat body 6: Seal body 9: Male screw 10: Valve hole 11: Valve seat 14: Female screw 18: Seal material 30: Communication hole 31: Valve room 32: paint passage

Claims (1)

(57) [Claims 1] A female screw formed at a distal end portion of a gun body is formed with a male screw screwed from the distal end side of the gun body, and a valve hole formed at the center is provided with a valve seat. And a central hole through which a valve rod that is screwed into a female screw formed on the inner periphery of the valve seat body and that is driven forward and backward from the rear of the gun body is inserted into close contact with the valve rod. A coating characterized by mounting an opening / closing valve unit comprising a seal body fitted with a sealing material and a communication hole communicating a paint passage formed in the gun body with a valve chamber formed in the valve seat body. For spray gun.