Airless Handheld Spray Gun

Abstract

To provide an airless portable spray gun that reduces the effect of the piston operating frequency on the spray painting effect. [Solution] The airless portable spray gun includes a housing, a tank, a nozzle 120, a pump body 140, a drive mechanism, and a discharge valve. The nozzle is provided at the front end of the housing. The pump body includes a pump chamber 141. The liquid supply end of the pump chamber is connected to the tank, and the liquid discharge end of the pump chamber is connected to the discharge valve via a first check valve. The discharge valve includes a valve body 210 having a buffer chamber 211, a valve seat 220, a valve head 230, and a spring 240 provided in the valve body. The valve seat is provided with a liquid discharge hole 224 communicating with the nozzle. The spring acts on the valve head to close the liquid discharge hole. The pump body sucks up liquid from the tank and pushes it into the buffer chamber. When the pressure in the buffer chamber exceeds a preset liquid discharge pressure, the valve head opens, and the liquid in the buffer chamber passes through the liquid discharge hole and is discharged from the nozzle.

Description

[Technical field]

[0001] The present invention relates to the technical field of spray guns, and more particularly to airless handheld spray guns. [Background technology]

[0002] Portable airless spray guns, also known as high-pressure portable airless spray guns, are spray guns that use a battery pack as a power source to pressurize paint, coating materials, etc. using a high-pressure plunger pump body before spraying.

[0003] In the case of conventional airless portable spray guns, the spray coating effect is often affected by the operating frequency of the piston in the plunger pump body. The higher the operating frequency of the piston, the more uniform the liquid discharged from the nozzle is, the less the intermittency of the spray coating, and the better the spray coating effect. On the other hand, when the operating frequency of the piston is low, the intermittency of the spray coating is more prominent, and the spray coating effect is reduced. Summary of the Invention [Problem to be solved by the invention]

[0004] The technical problem to be solved by the present invention is to reduce the influence of the operating frequency of the piston on the spray painting effect, avoid the intermittence of the spray painting when the piston operates at a low frequency, and improve the quality of the spray painting. [Means for solving the problem]

[0005] In order to achieve the above technical objectives, the airless portable spray gun provided by the present invention includes a housing, a tank, a nozzle, a pump body, a drive mechanism, and a discharge valve. The nozzle is provided at the front end of the housing. The pump body is provided with a pump chamber. The liquid supply end of the pump chamber is connected to the tank via a first check valve, and the liquid discharge end of the pump chamber is connected to the discharge valve via a second check valve. As a feature, the discharge valve includes a valve body, a valve seat, a valve head, and a spring. The valve body is provided with a buffer chamber. The valve seat, the valve head, and the spring are provided in the valve body. The valve seat is provided with a liquid discharge hole communicating with the nozzle. The spring acts on the valve head to bias the valve head in a direction to close the liquid discharge hole. The drive mechanism operates the pump body to suck up liquid from the tank and push it into the buffer chamber. When the pressure of the liquid in the buffer chamber exceeds a preset liquid discharge pressure, the valve head opens, and the liquid in the buffer chamber passes through the liquid discharge hole and is discharged from the nozzle.

[0006] Preferably, the valve seat includes a valve seat body and a tailstock. The tailstock is removably and fixedly connected to the valve seat body. The tailstock is attached to one end of the valve seat body remote from the nozzle. A position restriction chamber for positionally restricting the valve head and the spring is formed between the tailstock and the valve seat body. The valve head is movable within the position restriction chamber.

[0007] Preferably, the tail stock is hollow and has a liquid supply hole communicating with the liquid discharge hole. The valve head is capable of opening and closing the liquid discharge hole by opening and closing the liquid supply hole.

[0008] Preferably, the discharge valve further includes a valve stem. The valve stem is slidably disposed within the valve seat body. The valve stem and the valve seat body are circumferentially sealed to form a sealed chamber between the valve stem and the tailstock. A spring is disposed in the sealed chamber. One end of the spring abuts against the tailstock and the other end abuts against the valve stem. A valve head is disposed on the valve stem. The valve head includes a tapered head portion. A portion of the tapered head portion is inserted into the liquid discharge hole to close the liquid discharge hole.

[0009] Preferably, a fixed frame is provided within one end of the valve body adjacent to the pump body. The valve body further includes a valve stem. The valve head is fixed to the valve stem. The fixed frame is provided with a blind hole. One end of the valve stem is operably inserted into the blind hole. The spring has one end abutting the fixed frame and the other end abutting the valve stem. The valve head includes a tapered head. A portion of the tapered head is inserted into the discharge hole to close the discharge hole.

[0010] Preferably, the drive mechanism acts on the pump body to change the size of the pump chamber. A ratio of a maximum volume of the pump chamber to a volume of liquid that can be contained in the buffer chamber is 1:1 to 1:50.

[0011] Preferably, the pump body is further provided with a pressure reduction path. The pressure reduction path includes a first path communicating with the pump chamber and a second path communicating with the tank. A pressure reduction valve is provided between the first path and the second path. A preset pressure reduction pressure in the pressure reduction valve is greater than a preset liquid discharge pressure in the discharge valve.

[0012] Preferably, the pressure reducing valve includes a pressure reducing valve body, a pressure reducing tailstock, a pressure reducing valve stem, a pressure reducing valve head, and a pressure reducing spring. The pressure reducing valve body is provided with a first pressure reducing hole and a second pressure reducing hole that communicate with each other. The first pressure reducing hole communicates with the first passage, and the second pressure reducing hole communicates with the second passage. The pressure reducing valve stem is operably attached to the pressure reducing tailstock. The pressure reducing spring has one end abutting the pressure reducing tailstock and the other end abutting the pressure reducing valve stem. The pressure reducing valve head is fixed to the pressure reducing valve stem. The pressure reducing valve head is formed with a tapered surface. The pressure reducing spring acts on the pressure reducing valve stem to urge the tapered surface toward the first pressure reducing hole. When the pressure of the liquid in the buffer chamber is lower than a preset pressure reducing pressure, the first pressure reducing hole is closed by the pressure reducing valve head.

[0013] Preferably, the pressure reducing valve further includes a pressure reducing valve cover. The pressure reducing valve rod extends in a direction away from the first passage and penetrates the pressure reducing valve cover. An operating member is attached to the end of the pressure reducing valve rod. The operating member causes the pressure reducing valve head to open the first pressure reducing hole, thereby enabling spontaneous pressure reduction by the pressure reducing valve.

[0014] Preferably, the operating member includes a knob. The knob covers the pressure reducing valve cover and is rotatable relative to the pressure reducing valve cover. One of the pressure reducing valve cover and the knob is provided with a support portion, and the other is provided with an abutment portion. The pressure reducing spring acts on the knob to abut the abutment portion against the support portion. The support portion includes a first support portion and a second support portion. When the abutment portion abuts against the first support portion, the pressure reducing valve spontaneously reduces pressure, and when the abutment portion abuts against the second support portion, the pressure reducing valve stops spontaneously reducing pressure.

[0015] Preferably, the support portion further includes a spacer portion provided between the first support portion and the second support portion, the surface of the spacer portion gradually changing in a direction from the first support portion to the second support portion.

[0016] Preferably, the contact portion has a convex arcuate shape, and the second support portion has a concave arcuate shape that fits the contact portion.

[0017] Preferably, at least a portion of the first support portion has a concave arc shape that fits the contact portion. Effect of the Invention

[0018] By using the above technical means, the present invention has the following beneficial effects:

[0019] 1. The airless portable spray gun provided by this invention forms a buffer chamber in the valve body of the discharge valve, so that the liquid for spray painting is pre-pressurized in the buffer chamber before being discharged. A large amount of liquid for spray painting is stored in the buffer chamber, and the pressure of the liquid is uniform, so that the pressure of the discharged liquid can be maintained even between the suction of the pump body. This avoids interruptions in spray painting and improves the spray painting effect of the spray gun.

[0020] 2. A tailstock is provided at one end of the valve seat away from the nozzle, and the position of the valve head and spring is restricted between the valve seat body and the tailstock, so that the size of the valve seat can be reduced and the available volume of the buffer chamber can be increased. This allows the size of the discharge valve to be reduced on the premise of meeting the requirements of spray painting, thereby saving the material cost of the discharge valve. In addition, the tailstock and the valve seat body are removably and fixedly connected, which is convenient for removing the valve seat and cleaning the inside. In addition, a position restriction chamber is formed between the tailstock and the valve seat body. The valve head can move while being restricted within the position restriction chamber. The valve seat, the valve head and the spring form a removable modular structure, so that the valve head and the spring are not easily lost when removing the valve seat. In addition, it is more convenient for the user to assemble the valve seat and the valve body.

[0021] 3. The tailstock is equipped with a liquid supply hole, so that the liquid pressure in the buffer chamber can directly act on the valve head, which makes the valve head opening method simpler and improves the spray sensitivity of the spray gun.

[0022] 4. A valve stem is installed inside the valve body. The valve stem and the valve seat body are sealed in the circumferential direction to form a sealed chamber between the valve stem and the tailstock, and a spring is installed in the sealed chamber, which prevents the spring from rusting due to contact with liquid.

[0023] 5. One end of the valve rod is movably connected to the fixed frame, and the other end is fixed to the valve head. The valve head is provided with a tapered head for opening and closing the discharge hole. This structure is simple and reliable.

[0024] 6. The volume ratio of the pump chamber and the buffer chamber is set reasonably so that the buffer chamber can obtain good liquid storage effect and buffering effect, thereby improving the spray painting quality of the spray gun.

[0025] 7. The pump body is provided with a pressure reduction path. If the pressure in the buffer chamber or pump chamber becomes too high, the liquid will flow back directly from the pressure reduction path to the tank. This prevents the operating resistance from becoming too high and the drive mechanism from overheating.

[0026] 8. The pressure reducing valve further includes a pressure reducing valve cover. The pressure reducing valve rod passes through the pressure reducing valve cover, and an operating member is attached to the pressure reducing valve. The operating member opens the first pressure reducing hole in the pressure reducing valve head, allowing the pressure reducing valve to reduce pressure spontaneously. This allows the user to reduce pressure spontaneously using the pressure reducing valve, thereby preventing the buffer chamber from remaining in a high pressure state even after the airless portable spray gun is stopped.

[0027] 9. The operating member includes a knob. The knob covers the pressure reducing valve cover and is rotatable relative to the pressure reducing valve cover. When the abutment portion abuts against the first support portion, the pressure reducing valve spontaneously reduces pressure. When the abutment portion abuts against the second support portion, the pressure reducing valve stops spontaneous pressure reduction. This allows a user to rotate the knob to abut the abutment portion against a different position on the support portion, thereby enabling the pressure reducing valve to spontaneously reduce pressure or stop spontaneous pressure reduction. This makes it even easier to operate the operating member.

[0028] 10. The surface of the spacer part gradually changes from the first support part to the second support part. This allows the knob to cooperate with the spacer part, and switching between the first support part and the second support part is realized during the knob rotation process. The user can switch the position of the abutment part on the support part without lifting the knob during the knob rotation process, making it easier to spontaneously reduce pressure with the operating member.

[0029] 11. The abutment portion has a convex arcuate shape, and the second support portion has a concave arcuate shape that fits the abutment portion. This allows the abutment portion to slide more smoothly between the first support portion and the second support portion. In addition, the shapes of the second support portion and the abutment portion are adapted to each other. This allows the abutment portion and the second support portion to be better positioned when the pressure reducing valve stops spontaneous pressure reduction, and the relative movement between the two is reduced or avoided.

[0030] 12. At least a portion of the first support portion has a concave arc shape that fits the abutment portion. This allows the abutment portion to be positioned when abutting against the first support portion, thereby reducing or avoiding the abutment portion slipping off the first support portion during spontaneous decompression. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a structural diagram of a spray gun. [Diagram 2] FIG. 2 is a structural diagram of the pump body and valve body of the spray gun. [Diagram 3] FIG. 3 is a cross-sectional view of a portion of the structure in the front-rear direction when the first specific means is used in the discharge valve of a spray gun. [Figure 4] FIG. 4 is a structural diagram of a portion of FIG. [Diagram 5] FIG. 5 is a partial structural diagram of a valve head that is spherical. [Figure 6] FIG. 6 is a cross-sectional view of a portion of the structure in the front-rear direction when the second specific means is used in the discharge valve of a spray gun. [Figure 7] FIG. 7 is a structural diagram of a portion of FIG. [Figure 8] FIG. 8 is a cross-sectional view of a portion of the structure in the front-rear direction when the third specific means is used in the discharge valve of a spray gun. [Figure 9] FIG. 9 is a structural diagram of a portion of FIG. [Figure 10] FIG. 10 is a cross-sectional view of a part of the structure perpendicular to the front-rear direction when the first specific means is used in a pressure reducing valve of a spray gun. [Figure 11]FIG. 11 is a structural diagram of a portion of FIG. [Figure 12] FIG. 12 is a cross-sectional view of a part of the structure perpendicular to the front-rear direction when the second specific means is used in the pressure reducing valve of the spray gun. [Figure 13] FIG. 13 is a structural diagram of the pressure reducing valve cover in FIG. [Figure 14] FIG. 14 is a structural diagram of the knob in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The following describes and explains the technical means in the embodiments of the present invention in combination with the drawings of the embodiments of the present invention. However, the following embodiments are only preferred embodiments of the present invention, and are not all of the embodiments. Based on the embodiments in the embodiment, any other embodiments obtained by those skilled in the art without requiring creative labor are all within the scope of protection of the present invention.

[0033] Combining Figures 1 and 2, the airless portable spray gun provided in the embodiment of the present invention includes a housing 100, a tank 110, a nozzle 120, a pump body 140, a driving mechanism 130 and a discharge valve 200. The nozzle 120 is provided at the front end of the housing 100. The tank 110 is used to store liquid for spray painting. The pump body 140 is provided with a pump chamber 141. The supply end 141a of the pump chamber 141 is connected to the tank 110 through a first check valve 201, and the discharge end 141b of the pump chamber 141 is connected to the discharge valve 200 through a second check valve 202. The discharge valve 200 includes a valve body 210, a valve seat 220, a valve head 230 and a spring 240. The valve body 210 is provided with a buffer chamber 211. The valve seat 220, the valve head 230 and the spring 240 are provided in the valve body 210. The valve seat 220 is provided with a liquid discharge hole 224 that communicates with the nozzle 120. The spring 240 acts on the valve head 230 to urge the valve head 230 in a direction to close the liquid discharge hole 224. The drive mechanism 130 operates the pump body 140 to suck up liquid from the tank 110 and push it into the buffer chamber 211. When the pressure of the liquid in the buffer chamber 211 exceeds a preset liquid discharge pressure, the valve head 230 opens, and the liquid in the buffer chamber 211 passes through the liquid discharge hole 224 and is discharged from the nozzle 120.

[0034] By forming a buffer chamber 211 in the valve body 210 of the discharge valve 200, the liquid before being discharged is pre-pressurized in the buffer chamber 211. Since a large amount of liquid is stored in the buffer chamber 211 and the pressure of the liquid is relatively uniform, the pressure of the discharged liquid can be maintained even between the suction of the pump body 140. This prevents interruptions in spray painting and improves the spray painting effect of the spray gun.

[0035] The drive mechanism 130 is provided with a piston 131. The piston 131 changes the volume of the pump chamber 141 by reciprocating in the pump body 140. When the piston 131 moves backward, the volume of the pump chamber 141 increases, the first check valve 201 opens, and the liquid in the tank 110 flows into the pump chamber 141. In addition, the second check valve 202 prevents the liquid in the discharge valve 200 from flowing back into the pump chamber 141. When the piston 131 moves forward, the volume of the pump chamber 141 decreases, the second check valve 202 opens, and the liquid in the pump chamber 141 is pushed into the discharge valve 200. In addition, the first check valve 201 prevents the liquid in the pump chamber 141 from flowing back into the tank 110. The drive mechanism 130 and the pump body 140 are pumps whose volumes change, and conventional plunger pumps, diaphragm pumps, screw pumps, etc. can be used.

[0036] In this embodiment, a groove 226 is provided on the outer circumferential surface of the valve seat 220, and a seal ring is provided in the groove 226. The seal ring maintains a circumferential seal between the valve seat 220 and the valve body 210. This prevents the liquid in the buffer chamber 211 from leaking to the outside through a gap between the valve seat 220 and the valve body 210.

[0037] In this embodiment, the ratio between the maximum volume of the pump chamber 141 and the volume of liquid that the buffer chamber 211 can accommodate is 1:1 to 1:50 so that the buffer chamber 211 can obtain a better liquid storage effect and buffering effect. If the volume of the buffer chamber 211 is too large, the liquid remaining in the buffer chamber 211 cannot be discharged after the end of spray coating, and waste is likely to occur. On the other hand, if the volume of the buffer chamber 211 is too small, the liquid storage effect and buffering effect of the buffer chamber 211 are hindered. The spray coating quality of the spray gun is improved by setting the volume ratio between the pump chamber 141 and the buffer chamber 211 so that the buffer chamber 211 can obtain a better liquid storage effect and buffering effect. Preferably, the ratio between the maximum volume of the pump chamber 141 and the volume of liquid that the buffer chamber 211 can accommodate is 1:10 to 1:40. Furthermore, the volume ratio is 1:1 to 1:30. Furthermore, the volume ratio is 1:1 to 1:20. As a feasible implementation in this embodiment, these volume ratios may be set to values ​​such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc.

[0038] Combining FIG. 3 and FIG. 4, in the first specific means of the discharge valve 200 in this embodiment, a fixed frame 212 is provided at one end of the valve body 210 adjacent to the pump body 140. The fixed frame 212 is used to support the second check valve 202. At least one liquid supply hole 225 is formed in the fixed frame 212. The discharge valve 200 further includes a valve rod 260. The fixed frame 212 is provided with a blind hole 2121 at one end opposite to the second check valve 202. The rear end of the valve rod 260 is operably inserted into the blind hole 2121. In addition, the valve head 230 is fixed to the front end of the valve rod 260. The rear end of the spring 240 abuts against the fixed frame 212, and the front end abuts against the valve rod 260. The spring 240 biases the valve head 230 in a direction to close the liquid discharge hole 224. The valve head 230 includes a tapered head portion 231. A valve plate 250 is provided at the discharge hole 224. The valve plate 250 and the valve seat 220 are sealed in the axial direction. The valve plate 250 is provided with a through hole 251 that communicates with the discharge hole 224. A part of the tapered head portion 231 extends into the through hole 251 to close the discharge hole 224. In addition, another part of the tapered head portion 231 is located within the buffer chamber 211.

[0039] The pressure of the liquid in the buffer chamber 211 is applied to the valve head 230 from the circumferential direction. The pressure of the liquid can be decomposed into a force in a direction away from the liquid discharge hole 224 and a force in a direction toward the center of the valve head 230. The forces in the direction toward the center of the valve head 230 in the circumferential direction cancel each other out. On the other hand, when the total of the forces in the direction away from the liquid discharge hole 224 exceeds a preset liquid discharge pressure, the liquid moves the valve head 230 in a direction away from the liquid discharge hole 224. In other words, the valve head 230 opens the liquid discharge hole 224. The liquid enters the nozzle 120 from between the valve head 230 and the liquid discharge hole 224 and becomes available for discharge.

[0040] A fixed frame 212 is provided at one end of the valve body 210 adjacent to the pump body 140. The rear end of the valve stem 260 is operably connected to the fixed frame 212. A valve head 230 is fixed to the front end of the valve stem 260. The valve head 230 uses a tapered head 231 to close the discharge valve 200 and discharge liquid. This structure is simple, reliable, and low cost.

[0041] 5, based on the structure of the discharge valve 200 shown in FIG. 3 and FIG. 4, the valve head 230 may be spherical.

[0042] Combining FIG. 6 and FIG. 7, the second specific means of the discharge valve 200 is different from the first specific means in that the valve seat 220 includes a valve seat body 221 and a tailstock 222. The tailstock 222 is detachably and fixedly connected to the valve seat body 221. The tailstock 222 is attached to one end of the valve seat body 221 that is separated from the nozzle 120. A position restriction chamber 223 that restricts the position of the valve head 230 and the spring 240 is formed between the tailstock 222 and the valve seat body 221. The movement of the valve head 230 in the position restriction chamber 223 is subject to certain restrictions. By providing the tailstock 222 at one end of the valve seat 220 that is separated from the nozzle 120 and restricting the position of the valve head 230 and the spring 240 between the valve seat body 221 and the tailstock 222, the size of the valve seat 220 can be reduced, and the available volume of the buffer chamber 211 can be increased. This allows the size of the discharge valve 200 to be reduced on the premise of meeting the requirements of spray painting, so as to save the material cost of the discharge valve 200. In addition, the tailstock 222 and the valve seat body 221 are detachably connected, so that it is convenient to remove the valve seat 220 and clean the inside. In addition, a position restriction chamber 223 is formed between the tailstock 222 and the valve seat body 221 to positionally restrict the valve head 230 and the spring 240. The valve head 230 can move while being restricted in the position restriction chamber 223. The valve seat 220, the valve head 230 and the spring 240 form a detachable modular structure, so that the valve head 230 and the spring 240 are unlikely to be lost when removing the valve seat 220. In addition, it is more convenient for the user to assemble the valve seat 220 and the valve body 210. In this manner, the fixed frame 212 is fixed in the rear end of the buffer chamber 211. In addition, a liquid supply passage 227 is formed between the outer circumferential surface of the fixed frame 212 and the inner circumferential surface of the valve body 210 .

[0043] 7, the tailstock 222 is hollow and has a liquid supply hole 225 communicating with the liquid discharge hole 224. One end of the spring 240 abuts against the valve seat body 221, and the other end acts on the valve head 230 to urge the valve head 230 in the direction of the liquid supply hole 225. When the valve head 230 closes the liquid supply hole 225, there is no liquid flowing toward the liquid discharge hole 224, so the liquid discharge hole 224 is closed. The valve head 230 is spherical. The diameter of the valve head 230 is larger than the diameter of the liquid supply hole 225, and a part of the valve head 230 enters the liquid supply hole 225 to close the liquid supply hole 225. By forming the liquid supply hole 225 in the tailstock 222, the pressure of the liquid in the buffer chamber 211 can directly act on the valve head 230, so the opening method of the valve head 230 becomes simpler and the spray sensitivity of the spray gun becomes higher. The liquid pressure is applied to the valve head 230. When the liquid pressure becomes greater than a preset liquid discharge pressure, the valve head 230 moves away from the liquid supply hole 225. In some other equivalent embodiments, the valve head 230 may be tapered or may be at least partially tapered.

[0044] 8 and 9 , in the third specific embodiment of the discharge valve 200, the discharge valve 200 includes a valve rod 260. The valve rod 260 is slidably installed in the valve seat body 221. A seal ring is installed on the outer periphery of the valve rod 260, and the seal ring forms a circumferential seal between the valve rod 260 and the valve seat body 221. A portion of the position restriction chamber 223 located between the valve rod 260 and the tailstock 222 forms a sealing chamber 228. A spring 240 is installed in the sealing chamber 228. The rear end of the spring 240 abuts against the tailstock 222, and the front end of the spring 240 abuts against the valve rod 260. The valve head 230 is fixed to the front end of the valve rod 260. The valve head 230 is provided with a tapered head. A part of the tapered head extends into the through hole 251 of the valve plate 250 to close the liquid discharge hole 224. The liquid supply hole 225 is provided in the side wall of the valve seat body 221, and can communicate with the liquid discharge hole 224 through the position restriction chamber 223 and the through hole 251. In this manner, the fixed frame 212 is fixed in the rear end of the buffer chamber 211. A liquid supply passage 227 is formed between the outer peripheral surface of the fixed frame 212 and the inner peripheral surface of the valve body 210. The pressure of the liquid in the buffer chamber 211 is applied to the tapered head of the valve head 230 from the circumferential direction. The pressure of the liquid can be decomposed into a force in a direction away from the liquid discharge hole 224 and a force toward the center of the valve head 230. The forces toward the center of the valve head 230 cancel each other out. On the other hand, when the force in the direction away from the liquid discharge hole 224 exceeds a preset liquid discharge pressure, the liquid moves the valve head 230 in a direction away from the liquid discharge hole 224, opening the liquid discharge hole 224. Then, the liquid flows from the liquid discharge hole 224 toward the nozzle 120 and can be discharged to the outside, thereby achieving spray painting. In addition, since the spring 240 is provided inside the sealed chamber 228, it is possible to prevent the liquid from coming into contact with the spring 240 and causing the spring 240 to rust.

[0045] 10, based on the different discharge valves 200 in the three specific means described above, the pump body 140 is further provided with a pressure reduction path 270. The pressure reduction path 270 includes a first path 271 communicating with the pump chamber 141 and a second path 272 communicating with the tank 110. A pressure reduction valve 280 is provided between the first path 271 and the second path 272. A preset pressure reduction pressure in the pressure reduction valve 280 is greater than a preset liquid discharge pressure in the discharge valve 200.

[0046] Specifically, the pump body 140 is provided with a pressure reducing valve mounting portion 142 for mounting a pressure reducing valve 280. A first path 271 is provided between the pump chamber 141 and the pressure reducing valve mounting portion 142, and a second path 272 is provided between the tank 110 and the pressure reducing valve mounting portion 142. The pressure reducing valve 280 closes the first path 271 to regulate the liquid in the buffer chamber 211 from flowing into the tank 110. The pressure reducing valve 280 opens when the pressure of the liquid exceeds a preset pressure reducing pressure. When the pressure reducing valve 280 opens, the liquid in the pump chamber 141 flows back into the tank 110, thereby preventing the pressure of the liquid in the buffer chamber 211 from becoming too high. In addition, when the pressure of the liquid in the buffer chamber 211 becomes too high, the liquid in the buffer chamber 211 flows back directly from the pressure reducing path 270 to the tank 110, so that the operating resistance becomes too high and the driving mechanism 130 generates heat can be prevented.

[0047] In the first specific means shown in FIG. 10, the pressure reducing valve 280 is located in the housing 100. The pressure reducing valve 280 is removably mounted in the pressure reducing valve mounting portion 142. The pressure reducing valve 280 includes a casing 281, a pressure reducing tailstock 282, a pressure reducing valve rod 283, a pressure reducing valve head 284, and a pressure reducing spring 285. The casing 281 is provided with a first pressure reducing hole 2811 and a second pressure reducing hole 2812 that can communicate with each other. The first pressure reducing hole 2811 communicates with the first passage 271, and the second pressure reducing hole 2812 communicates with the second passage 272. The pressure reducing valve rod 283 is operably provided in the casing 281 and the pressure reducing tailstock 282. One end of the pressure reducing spring 285 abuts against the pressure reducing tailstock 282, and the other end of the pressure reducing spring 285 abuts against the pressure reducing valve rod 283. The pressure reducing valve head 284 is provided at one end of the pressure reducing valve rod 283 facing the first pressure reducing hole 2811. The pressure reducing spring 285 has elastic force. The pressure reducing spring 285 acts on the pressure reducing valve rod 283 to bias the pressure reducing valve head 284 in a direction to close the first pressure reducing hole 2811. The pressure reducing valve head 284 closes the first pressure reducing hole 2811, thereby making it possible to prevent the liquid in the buffer chamber 211 from flowing back from the pressure reducing path 270. In addition, the elastic force of the pressure reducing spring 285 acting on the pressure reducing valve head 284 determines the magnitude of the pressure reducing pressure that is set in advance. When the pressure of the liquid in the buffer chamber 211 exceeds the preset pressure reducing pressure, the liquid moves the pressure reducing valve head 284, and the pressure reducing valve head 284 opens the first pressure reducing hole 2811. Then, the liquid in the buffer chamber 211 flows in from the first path 271 and flows back to the tank 110 via the first pressure reduction hole 2811, the second pressure reduction hole 2812, and the second path 272. The pressure reduction valve 280 is further provided with a pressure reduction valve plate 286 at one end adjacent to the first path 271. The pressure reduction valve plate 286 is provided between the casing 281 and the pump body 140. The pressure reduction valve plate 286 prevents leakage between the first path 271 and the first pressure reduction hole 2811. The pressure reduction valve head 284 is formed with a tapered surface 2841. The tapered surface 2841 is pressed against the first pressure reduction hole 2811 to close the first pressure reduction hole 2811 when the pressure of the liquid in the buffer chamber 211 is lower than a preset pressure reduction pressure. In this means, the pressure reduction valve head 284 and the pressure reduction valve rod 283 may be integrally molded.Also, the pressure reducing valve head 284 and the pressure reducing valve rod 283 may be assembled after being molded separately. In addition, in this embodiment, the pressure reducing valve head 284 may be provided in a cone shape or a spherical shape.

[0048] 10 and 11 , in this means, the second path 272 may also serve as an exhaust passage for discharging gas in the tank 110 to the outside. The pump body 140 is provided with an exhaust base 310 and an exhaust plug 320. The exhaust base 310 is provided with an exhaust hole 311 that communicates with the second path 272. The exhaust plug 320 is removably inserted into the exhaust hole 311 and is used to open and close the exhaust hole 311.

[0049] In addition, the pressure reducing valve 280 further includes a pressure reducing valve cover 286. The pressure reducing valve rod 283 extends along the axial direction of the first passage 271 and extends from the pressure reducing valve cover 286. An operating member 290 is attached to the end of the pressure reducing valve rod 283. The user can move the pressure reducing valve rod 283 by the operating member 290 in a direction away from the first passage 271 so that the pressure reducing valve head 284 opens the first pressure reducing hole 2811, thereby causing the pressure reducing valve 280 to perform spontaneous pressure reduction. By providing the pressure reducing valve 280 in this manner, the user can perform spontaneous pressure reduction by the pressure reducing valve 280, thereby preventing the buffer chamber 211 from maintaining a high pressure state even after the airless portable spray gun is stopped. Specifically, the operating member 290 is a pull rod or a lever. The user can achieve spontaneous pressure reduction by pulling or rotating the operating member 290. The force application direction of the pull rod or lever and the movement direction of the pressure reducing valve rod 283 are parallel to each other. This allows the user to more directly carry out voluntary pressure reduction operations.

[0050] 12, 13, and 14, in the second specific means of the pressure reducing valve 280, the operating member 290 is a knob 291. The knob 291 covers the outside of the pressure reducing valve cover 286 and is rotatable relative to the pressure reducing valve cover 286. The pressure reducing valve cover 286 is provided with a support portion 292, and the knob 291 is provided with an abutment portion 293. The pressure reducing spring 285 acts on the knob 291 to abut the abutment portion 293 against the support portion 292. The support portion 292 includes a first support portion 2921 and a second support portion 2922 having different protruding heights. The first support portion 2921 and the second support portion 2922 respectively support the abutment portion 293 at different positions. When the abutment portion 293 abuts against the first support portion 2921, the pressure reducing valve 280 is capable of spontaneous pressure reduction. Also, when the abutment portion 293 abuts against the second support portion 2922, the pressure reducing valve 280 stops spontaneous pressure reduction. As an alternative, the abutment portion 293 may be provided on the pressure reducing valve cover 286. In this case, the support portion 292 is provided on the knob 291. The user can rotate the knob 291 to bring the abutment portion 293 into abutment with different positions on the support portion 292, thereby realizing spontaneous pressure reduction or stopping spontaneous pressure reduction by the pressure reducing valve 280. This makes it easier to operate the operating member 290. Specifically, both the end of the pressure reducing valve rod 283 and the knob 291 are provided with holes. The pressure reducing valve rod 283 can be moved by inserting positioning pins into both holes and rotating the knob 291.

[0051] In addition, the support portion 292 further includes a spacer portion 2923 provided between the first support portion 2921 and the second support portion 2922. The surface of the spacer portion 2923 gradually changes from the first support portion 2921 to the second support portion 2922.

[0052] The knob 291 can cooperate with the spacer portion 2923 so that switching between the first support portion 2921 and the second support portion 2922 can be achieved when the knob 291 is rotated. The user can switch the position of the abutment portion 293 on the support portion 292 without lifting the knob 291 in the process of rotating the knob 291, which makes it even easier to spontaneously operate the operating member 290 to reduce pressure.

[0053] Preferably, the abutment portion 293 has a convex arcuate shape, and the second support portion 2922 has a concave arcuate shape that fits the abutment portion 293. This allows the abutment portion 293 to be switched more smoothly between the first support portion 2921 and the second support portion 2922. Furthermore, the shapes of the second support portion 2922 and the abutment portion 293 are adapted to each other. This allows the abutment portion 293 and the second support portion 2922 to be better positioned when the pressure reducing valve 280 stops reducing pressure, and the relative movement between them is reduced or avoided.

[0054] Preferably, at least a portion of the first support portion 2921 has a concave arc shape that fits the abutment portion 293. This allows the abutment portion 293 to be positioned when abutting against the first support portion 2921, thereby reducing or avoiding the situation where the abutment portion 293 slips off the first support portion 2921 during spontaneous decompression.

[0055] The above description is merely a specific embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the contents described in the drawings and the above specific embodiment. In addition, any modifications that do not deviate from the function and structural principle of the present invention are included in the scope of the utility model registration claims. [Explanation of symbols]

[0056] 100 Housing 110 Tank 120 Nozzle 130 Drive mechanism 131 Piston 140 Pump body 141 Pump Room 141a Liquid supply end 141b Liquid discharge end 142 Pressure reducing valve mounting part 200 Discharge valve 201 First check valve 210 Valve body 211 Buffer Room 212 Fixed Frame 2121 Blind hole 220 Valve seat 221 Valve seat body 222 Tailstock 223 Position control room 224 Liquid discharge hole 225 Liquid supply hole 226 Groove 227 Liquid supply channel 228 Sealed room 230 Bento 231 Tapered head 240 Spring 250 Valve plate 260 Valve stem 270 Decompression Path 271 Route 1 272 Route 2 280 Pressure reducing valve 281 Pressure reducing valve casing 2811 First decompression hole 2812 Second decompression hole 282 Reduced Pressure Tailstock 283 Pressure Reducing Valve Rod 284 Pressure reducing valve head 2841 Tapered surface 285 Pressure reducing spring 286 Pressure Reducing Valve Cover 290 Operating member 291 Picking 292 Support part 2921 1st support part 2922 Second support part 2923 Spacer part 293 Contact part 310 Exhaust Base 311 Exhaust Vent 320 Exhaust plug

Claims

1. An airless portable spray gun comprising a housing (100), a tank (110), a nozzle (120), a pump body (140), a drive mechanism (130) and a discharge valve (200), wherein the nozzle (120) is provided at a front end of the housing (100), the pump body (140) is provided with a pump chamber (141), a liquid supply end (141a) of the pump chamber (141) is connected to the tank (110) via a first check valve (201), and a liquid discharge end (141b) of the pump chamber (141) is connected to the discharge valve (200) via a second check valve (202), The discharge valve (200) includes a valve body (210), a valve seat (220), a valve head (230), and a spring (240). The valve body (210) is provided with a buffer chamber (211). The valve seat (220), the valve head (230), and the spring (240) are provided within the valve body (210). The valve seat (220) is provided with a liquid discharge hole (224) communicating with the nozzle (120). The spring (240) acts on the valve head (230) in a direction to close the liquid discharge hole (224). a valve head (230) biasing the valve head (230) to a position opposite to the tank (110), and the drive mechanism (130) operates a pump body (140) to suck up liquid from the tank (110) and push it into a buffer chamber (211), and when the pressure of the liquid in the buffer chamber (211) exceeds a preset liquid discharge pressure, the valve head (230) opens, causing the liquid in the buffer chamber (211) to pass through a liquid discharge hole (224) and be discharged from a nozzle (120).

2. The airless portable spray gun of claim 1, characterized in that the valve seat (220) includes a valve seat body (221) and a tailstock (222), the tailstock (222) is removably fixedly connected to the valve seat body (221), the tailstock (222) is attached to one end of the valve seat body (221) remote from the nozzle (120), a position control chamber (223) that positions the valve head (230) and the spring (240) is formed between the tailstock (222) and the valve seat body (221), and the valve head (230) is movable within the position control chamber (223).

3. An airless portable spray gun as described in claim 2, characterized in that the tailstock (222) is hollow and has a liquid supply hole (225) that communicates with the liquid discharge hole (224), and the valve head (230) is capable of opening and closing the liquid discharge hole (224) by opening and closing the liquid supply hole (225).

4. The airless portable spray gun according to claim 2, wherein the discharge valve (200) further includes a valve stem (260), the valve stem (260) being slidably disposed within the valve seat body (221), the valve stem (260) and the valve seat body (221) being sealed in the circumferential direction to form a sealed chamber (228) between the valve stem (260) and the tailstock (222), a spring (240) being disposed in the sealed chamber (228), one end of the spring (240) abutting against the tailstock (222) and the other end abutting against the valve stem (260), a valve head (230) being disposed on the valve stem (260), the valve head (230) including a tapered head portion (231), a portion of the tapered head portion (231) being inserted into the liquid discharge hole (224) to close the liquid discharge hole (224).

5. The airless portable spray gun of claim 1, characterized in that a fixed frame (212) is provided within one end of the valve body (210) adjacent to the pump body (140), the valve body (210) further includes a valve stem (260), the valve head (230) is fixed to the valve stem (260), the fixed frame (212) is provided with a blind hole (2121), one end of the valve stem (260) is operably inserted into the blind hole (2121), the spring (240) has one end abutting the fixed frame (212) and the other end abutting the valve stem (260), the valve head (230) includes a tapered head portion (231), a portion of the tapered head portion (231) is inserted into the liquid discharge hole (224) to close the liquid discharge hole (224).

6. The airless portable spray gun of claim 1, characterized in that the drive mechanism (130) acts on the pump body (140) to change the size of the pump chamber (141), and the ratio of the maximum volume of the pump chamber (141) to the volume of liquid that the buffer chamber (211) can accommodate is 1:1 to 1:

50.

7. The airless portable spray gun according to claim 1, further comprising a pressure reduction path (270) provided in the pump body (140), the pressure reduction path (270) including a first path (271) communicating with the pump chamber (141) and a second path (272) communicating with the tank (110), a pressure reduction valve (280) provided between the first path (271) and the second path (272), and a preset pressure reduction pressure in the pressure reduction valve (280) being greater than a preset liquid discharge pressure in the discharge valve (200).

8. The pressure reducing valve (280) includes a pressure reducing valve body (281), a pressure reducing tailstock (282), a pressure reducing valve rod (283), a pressure reducing valve head (284) and a pressure reducing spring (285). The pressure reducing valve body (281) is provided with a first pressure reducing hole (2811) and a second pressure reducing hole (2812) which are in communication with each other. The first pressure reducing hole (2811) is in communication with the first passage (271) and the second pressure reducing hole (2812) is in communication with the second passage (272). The pressure reducing valve rod (283) is operably attached to the pressure reducing tailstock (282). The pressure reducing spring (285) has one end connected to the pressure reducing tailstock (282). 82) at one end and abutting against a pressure reducing valve stem (283) at the other end, the pressure reducing valve head (284) being fixed to the pressure reducing valve stem (283), the pressure reducing valve head (284) being formed with a tapered surface (2841), the pressure reducing spring (285) acting on the pressure reducing valve stem (283) to urge the tapered surface (2841) in the direction of the first pressure reducing hole (2811), and when the pressure of the liquid in the buffer chamber (211) is lower than a preset pressure reducing pressure, the first pressure reducing hole (2811) is closed by the pressure reducing valve head (284).

9. The airless portable spray gun of claim 8, characterized in that the pressure reducing valve (280) further includes a pressure reducing valve cover (286), the pressure reducing valve rod (283) extends in a direction away from the first path (271) and penetrates the pressure reducing valve cover (286), and an operating member (290) is attached to an end of the pressure reducing valve rod (283).The operating member (290) opens the first pressure reducing hole (2811) in the pressure reducing valve head (284), thereby enabling the pressure reducing valve (280) to spontaneously reduce pressure.

10. The operating member (290) includes a knob (291), which covers the pressure reducing valve cover (286) and is rotatable relative to the pressure reducing valve cover (286). One of the pressure reducing valve cover (286) and the knob (291) is provided with a support portion (292), and the other is provided with an abutment portion (293). The pressure reducing spring (285) acts on the knob (291) to rotate the abutment portion (293) relative to the support portion (292). The airless portable spray gun of claim 9, characterized in that the support portion (292) is abutted against a first support portion (2921) and a second support portion (2922), and when the abutment portion (293) abuts against the first support portion (2921), the pressure reducing valve (280) spontaneously reduces pressure, and when the abutment portion (293) abuts against the second support portion (2922), the pressure reducing valve (280) stops spontaneously reducing pressure.

11. The airless portable spray gun of claim 10, characterized in that the support portion (292) further includes a spacer portion (2923) provided between the first support portion (2921) and the second support portion (2922), and the surface of the spacer portion (2923) gradually changes in the direction from the first support portion (2921) to the second support portion (2922).

12. The airless portable spray gun of claim 11, characterized in that the abutment portion (293) has a convex arcuate shape, and the second support portion (2922) has a concave arcuate shape that fits the abutment portion (293).

13. The airless portable spray gun according to claim 12, characterized in that at least a portion of the first support portion (2921) has a concave arc shape that fits the abutment portion (293).

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