JP5222039B2 - Spray gun - Google Patents

Description

  The present invention relates to a spray gun in which an air valve and a needle valve, which is a paint valve, are formed coaxially, and the air valve can be smoothly slid by a trigger.

 In the spray gun, as shown in FIG. 8, the paint flow path a having the paint discharge port a1 and the paint from the paint discharge port a1 are atomized by opening around the paint discharge port a1 and discharging air. An air flow path b having an air discharge port b1 to be sprayed, a needle valve c which is a paint valve for opening and closing the paint flow path a, and an air valve d for opening and closing the air flow path b. In order to prevent dripping of the paint from the paint discharge port a1, it is necessary to operate the air valve d prior to the needle valve c. Therefore, in the prior art, as shown in the figure, the needle valve c and the air valve d are provided separately, and the needle valve c and the air valve d are operated with a time difference by pulling the trigger e. It is configured.

  On the other hand, in recent years, in order to simplify the structure and reduce the cost, as shown in FIG. 9, a needle valve c and an air valve d are formed coaxially (see, for example, Patent Document 1). ). In this coaxial type, a tubular valve that is extrapolated to the needle valve c is used as the air valve d, and in order to slidably guide the tubular air valve d back and forth, Caps g having guide holes g1 through which the air valve d is inserted are attached to the front end and the rear end.

JP 2008-23465 A

  However, as is well known, the trigger e is pulled so as to tilt back and forth about the pivot point p at its upper end. Therefore, during traction, a component force in a direction intersecting with the axial direction of the air valve d necessarily acts on the air valve d. As a result, slippage between the air valve d and the guide hole g1 is deteriorated, the smoothness of the sliding operation of the air valve d is impaired, the traction becomes heavy, and the air valve d is curved and deformed. Problems also arise. In the past, the air valve d was divided into the front part d1 and the rear part d2 in the space between the caps g and g to reduce the influence on slipping and bending, but it has reached a sufficiently satisfactory level. Not in.

  Therefore, the present invention is based on the trigger based on the principle that the air valve is formed as an elongated body that is not divided at least between the caps, and the air valve is loosely inserted into the guide hole of each cap with a large play. An object of the present invention is to provide a spray gun capable of smoothing the sliding operation of the air valve, enhancing the pulling operability of the trigger, and suppressing the curved deformation of the air valve.

In order to achieve the above object, the invention of claim 1 of the present application is such that the gun body has a paint flow path having a paint discharge port opened and closed by a needle valve, and is opened around the paint discharge port to discharge air. An air flow path having an air discharge port for atomizing and spraying paint from the paint discharge port, an air valve means for opening and closing the air flow path, and a trigger for sequentially operating the air valve means and the needle valve Spray gun,
The air valve means includes
A valve housing hole formed in the gun body,
A valve seat that is mounted in the valve storage hole and divides the valve storage hole into front and rear air chambers;
An air valve having a base tube portion slidably inserted back and forth in the needle valve, and a valve portion swelled at an intermediate position in the longitudinal direction of the base tube portion and capable of opening and closing the valve seat;
A front holding means having a front cap provided with a guide hole for closing the front end of the front air chamber and guiding the air valve back and forth through the base tube portion;
And a rear holding means having a rear cap provided with a guide hole for closing the rear end of the rear air chamber and guiding the air valve back and forth through the base tube portion,
Each of the front and rear guide holes is characterized in that the base tube portion is loosely inserted with a play that can tilt at a swing angle θ of 1 ° or more with respect to the center line of each guide hole.

Further, in the invention of claim 2, the front cap and the rear cap include a seal housing recess that is continuous with each guide hole via a stepped surface portion and has an inner peripheral surface portion that is larger in diameter and concentric than the guide hole,
And a radially inner contact piece that contacts the outer peripheral surface of the base tube portion and a radially outer contact that contacts the inner peripheral surface portion of the seal housing recess in the seal housing recess. An elastic seal member having a U-shaped cross-section composed of one piece and a joint piece extending along the stepped surface portion and between the inner and outer contact piece portions is accommodated, and the seal member is free before being accommodated. In the state, the inner and outer contact piece portions are opened in a C shape toward the tip.

  According to a third aspect of the present invention, the valve housing hole has a holding surface portion that receives and holds the outer peripheral surface of the front cap at the front end portion thereof, and the inner diameter Di of the holding surface portion is equal to the outer peripheral surface of the front cap. The front cap is held with play on the holding surface portion by being 0.3 mm or more larger than the outer diameter Do.

In the invention of claim 4, the needle valve has a contact portion that contacts the rear end of the air valve at the rear end portion,
By the initial pulling of the trigger, the air valve is retracted to open the valve seat, and by further pulling, the air valve comes into contact with the contact portion of the needle valve, and the needle valve is integrated with the air valve. The paint discharge port is opened by retreating.

  Since the present invention is configured as described above, the sliding operation of the air valve by the trigger can be smoothed. Therefore, the pulling operation of the trigger can be performed lightly, and the curved deformation of the air valve can be suppressed.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the spray gun of the present invention.
In FIG. 1, a spray gun 1 according to this embodiment includes a paint flow path 5 having a paint discharge port 4 opened and closed by a needle valve 3 in a gun body 2, and an air discharge port 6 that opens around the paint discharge port 4. And an air valve means 8 for opening and closing the air flow path 7, and a trigger 9 for sequentially operating the air valve means 8 and the needle valve 3. Then, the paint from the paint discharge port 4 is atomized and sprayed by discharging air from the air discharge port 6.

  The gun body 2 has a pistol shape in which a head portion 11 and a handle 12 are formed at a front end and a rear end of a barrel portion 10 extending in the front-rear direction. It pivots around the pivot point P so that it can tilt back and forth.

  The head 11 is formed with a paint flow path 5 extending from the paint discharge port 4 opened on the front surface to the paint intake 13 provided on, for example, the lower surface (or side surface) of the head 11. . In this example, the paint flow path 5 includes a paint main flow path portion 5A concentrically extending rearward from the paint discharge port 4 and a paint sub flow path extending from the paint intake port 13 to the paint main flow path portion 5A. Part 5B. The rear end of the paint main flow path portion 5A is closed by a closing metal fitting 14.

  The needle valve 3 is a shaft-like body that extends concentrically with the paint main flow path portion 5A through the paint main flow path portion 5A, and the needle valve 3 has a front end portion separated from the paint discharge port 4. The paint discharge port 4 can be opened and closed by contact. Further, the rear end side of the needle valve 3 extends through a valve fitting hole 16 provided in the handle 12 after passing through the closing fitting 14. The needle valve 3 and the closing fitting 14 are shaft-sealed by a sealing material such as an O-ring.

  In addition, an annular air discharge port 6 concentrically surrounding the paint discharge port 4 is disposed on the front surface of the head 11, and the gun body 2 is connected to the gun body 2 from the air discharge port 6 in the present example. For example, an air flow path 7 extending to the air intake 15 provided on the lower surface of the handle 12 is formed.

  The air flow path 7 is provided in the air inlet flow path 7A extending from the air intake port 15 to the first connection port P1 provided in the valve storage hole 16, the valve storage hole 16 and the air flow path 7. The air outflow passage 7B extends from the second connection port P2 positioned in front of the first connection port P1 to the air discharge port 6.

  The valve storage hole 16 stores air valve means 8 for opening and closing the air flow path 7. The valve storage hole 16 is concentric with the paint main flow path portion 5A, and in this example, as shown in an enlarged view in FIG. The Specifically, the valve housing hole 16 includes a small-diameter portion 16A on the front end side, an intermediate-diameter portion 16B connected to the small-diameter portion 16A via the first step Sa and having a larger diameter than the small-diameter portion 16A, The large-diameter portion 16C is connected to the intermediate-diameter portion 16B via the second step Sb and has a larger diameter than the intermediate-diameter portion 16B.

  The air valve means 8 is mounted in the valve storage hole 16, and the valve storage hole 16 is connected to the front air chamber Hf having the second connection port P2 and the rear port having the first connection port P1. A valve seat 20 divided into an air chamber Hr, an air valve 21 extrapolated to the needle valve 3, a front holding means 22 for closing a front end portion of the front air chamber Hf, and a rear end portion of the rear air chamber Hf After the closing, holding means 23 is included.

  In this example, the valve seat 20 includes a valve seat bracket 20A that is locked to the second step Sb, and the valve seat bracket 20A that is screwed to the large-diameter portion 16C and the second step Sb. It is formed from a valve seat fixing ring 20B that is fixed with a narrow pressure therebetween.

  The air valve 21 is externally slidably inserted in the front and back of the needle valve 3, and is swelled at an intermediate position in the longitudinal direction of the base tube portion 24 and can open and close the valve seat 20. And a valve portion 25. An engagement portion 26 is provided at the front end of the base tube portion 24 to engage the trigger 9 and move the air valve 21 back and forth by a trigger operation.

  The front holding means 22 has a front cap 27 which closes the front end of the front air chamber Hf and has a guide hole 27a through which the air valve 21 is guided back and forth through the base tube portion 24. . The front cap 27 is engaged with the first step Sa between the small diameter portion 27A loosely inserted into the small diameter portion 16A of the valve housing hole 16 and the large diameter portion 27B loosely inserted into the intermediate diameter portion 16B. It consists of a stepped ring body provided with a step K to be stopped.

  The front cap 27 is biased forward by a coil spring-like spring means 29 disposed between the valve seat bracket 20A and an O-ring 28 is disposed between the steps Sa and K. A seal is made between the valve housing hole 16 and the front cap 27.

  Further, a seal between the front cap 27 and the base tube portion 24 is accommodated by accommodating an elastic seal member 31 made of plastic or rubber in a seal accommodating recess 30 formed in the front cap 27 and having a rear end opened. Is done. A pressing plate 32 is interposed between the front cap 27 and the spring means 29, and the pressing plate 32 prevents the elastic seal member 31 from coming off from the seal housing recess 30.

  Next, the rear holding means 23 has a rear cap provided with a guide hole 33a for closing the rear end portion of the rear air chamber Hr and inserting the base tube portion 24 to guide the air valve 21 back and forth. 33. The rear cap 33 is a screw cap that is screwed into the large-diameter portion 16C of the valve storage hole 16, and includes a seal storage recess 35 on the front side of the rear guide hole 33a and a paint adjustment on the rear side. Screw screw recesses 37 are respectively formed.

  A coil spring-like spring means 38 that biases the valve portion 25 forward is interposed between the valve portion 25 and the rear cap 33. Normally, the valve portion 25 is pressed against the valve seat 20 to The valve seat 20 can be closed. Also, the air valve 21 can overcome the spring means 38 by the pulling operation of the trigger 9 and can be moved backward to open the valve seat 20. A contact portion 3 </ b> A that contacts the rear end of the air valve 21 is provided at the rear end portion of the needle valve 3. Therefore, in the initial traction of the trigger 9, only the valve seat 20 is opened, and in the further traction, the air valve 21 contacts the contact portion 3A and the needle valve 3 moves backward together with the air valve 21. Thus, the paint discharge port 4 can be opened.

  An elastic seal member 34 made of plastic or rubber is housed in the seal housing recess 35, and the space between the rear cap 33 and the base tube portion 24 is sealed. A pressing plate 39 is interposed between the rear cap 33 and the spring means 38, and the pressing plate 39 prevents the elastic seal member 34 from coming off from the seal housing recess 35.

  A paint adjusting screw 40 is screwed into the paint adjusting screw screw recess 37. A concave portion 40A concentric with the needle valve 3 is formed at the front end of the paint adjusting screw 40, and the needle valve 3 is urged forward between the bottom surface and the needle valve 3, and is always Coil spring-like spring means 42 for closing the paint discharge port 4 is provided. The paint adjusting screw 40 can adjust the retreat distance of the needle valve 3 by adjusting the screw advance and retreat, and can adjust the paint discharge amount from the paint discharge port 4.

  Next, in the guide holes 27a and 33a, as shown in FIGS. 3 and 4, the base tube portion 24 is moved at a deflection angle θ of 1 ° or more with respect to the center line i of each guide hole 27a and 33a. It is inserted with a large play that can be tilted. Here, the deflection angle θ means the maximum deflection angle of the base tube portion 24 when the base tube portion 24 is held by only one guide hole. As shown in FIG. The maximum deflection angle θ1max of the base tube portion 24 when the tube portion 24 is held is 1 ° or more, and as shown in FIG. 4, the base tube portion when the base tube portion 24 is held only by the guide hole 33a. This means that the maximum deflection angle θ2max of 24 is 1 ° or more. Such a large deflection angle θ is set by adjusting the difference between the inner diameter of the guide holes 27a and 33a and the outer diameter of the base tube portion 24 and the length of the guide holes 27a and 33a in the axial direction. it can. The upper limit of the deflection angle θ, that is, the upper limit of the deflection angles θ1max and θ2max is preferably 5 ° or less.

  In this way, the base tube portion 24 is guided by the guide holes 27a and 33a with a large play that can be tilted at a swing angle θ of 1 ° or more. Therefore, even when a component force in a direction crossing the axial center direction acts on the air valve 21 at the time of pulling the trigger, the air valve 21 (base tube portion 24) is tilted, and the guide holes 27a and 33a Sliding can be maintained satisfactorily, the smoothness of sliding of the air valve 21 can be improved, and curved deformation between the guide holes 27a and 33a of the air valve 21 can be suppressed.

  However, when having such a large play, it is necessary to employ the following sealing means in order to seal between the base tube portion 24 and the guide holes 27a and 33a while exhibiting the above advantages. . Specifically, as the seal accommodating recess 30, as shown in FIG. 5A, the inner peripheral surface portion 30B is connected to the guide hole 27a via the step surface portion 30A and has a larger diameter and concentricity than the guide hole 27a. Is provided. In the seal housing recess 30, a radially inner contact piece 31 i that contacts the outer peripheral surface of the base tube portion 24 and a radially outer surface that contacts the inner peripheral surface portion 30 B of the seal housing recess 30. An elastic seal member 31 having a U-shaped cross section is provided, which includes an outer contact piece portion 31o and a joint piece portion 31m that extends along the stepped surface portion 30A and connects the inner and outer contact piece portions 30i and 30o. Yes.

  The seal housing recess 35 is also the same. As shown in FIG. 5B, an inner peripheral surface portion 35B that is continuous with the guide hole 33a through a step surface portion 35A and is larger in diameter and concentric than the guide hole 33a. Provided. In the seal housing recess 35, a radially inner contact piece 34 i that contacts the outer peripheral surface of the base tube portion 24 and a radially outer surface that contacts the inner peripheral surface portion 35 B of the seal housing recess 35. An elastic seal member 34 having a U-shaped cross section is provided which includes an outer contact piece 34o and a joint piece 34m that extends along the stepped surface 35A and connects the inner and outer contact pieces 34i and 34o. Yes.

  As shown in FIG. 6, the elastic sealing members 31 and 34 have their inner contact piece portions 31i and 34i and outer contact piece portions 31o and 34o, respectively, in the free state before housing. Inclined so that the legs spread like a letter C. In this way, even when there is a large play, the inner contact piece portions 31i, 34i can be in pressure contact with the base tube portion 24 and the outer contact piece portions 31o, 34o can press-contact with inner peripheral surface parts 30B and 35B, and can perform a reliable seal. Particularly, since the pressure contact force is obtained by the bending elastic force of the inner contact piece portions 31i and 34i and the outer contact piece portions 31o and 34o, a relatively uniform pressure contact force can be obtained even for a large displacement. It is possible to obtain the sealing effect stably.

  Further, in this example, in order to make the air valve 21 slide more smoothly, the front cap 27 is attached to the front end portion of the valve housing hole 16 with play as shown in an enlarged view in FIG. ing. Specifically, the difference (Di−Do) between the outer diameter Do of the outer peripheral surface of the front cap 27 and the inner diameter Di of the holding surface portion 41 of the valve storage hole 16 that receives and holds the outer peripheral surface is set to 0.3 mm or more. ing. Specifically, in this example, the difference between the outer diameter DoA of the small-diameter portion 27A of the front cap 27 and the inner diameter DiA of the small-diameter portion 16A of the valve housing hole 16 serving as the holding surface portion 41 that receives the small-diameter portion 27A ( DiA-DoA) is set to 0.3 mm or more, and the outer diameter DoB of the large-diameter portion 27B of the front cap 27 and the intermediate-diameter portion of the valve housing hole 16 that is the holding surface portion 41 that receives the large-diameter portion 27B. The difference (DiB-DoB) from the inner diameter DiB at 16B is set to 0.3 mm or more. Thereby, the front cap 27 itself can also be tilted with respect to the valve housing hole 16, and the sliding operation of the air valve 21 can be made smoother.

  The upper limit of the deflection angle θ is not particularly limited, but if it is too large, the sealing effect by the elastic seal members 31 and 34 tends not to be exhibited sufficiently. Therefore, the upper limit of the deflection angle θ is preferably 5 ° or less, more preferably 3 ° or less. Similarly, if the difference (Di-Do) is too large, the sealing effect by the O-ring 28 tends not to be sufficiently exhibited. Therefore, the upper limit of the difference (Di−Do) is preferably 0.8 mm or less.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

It is side part sectional drawing which shows one Example of the spray gun of this invention. It is a side view which expands and shows an air valve means. It is sectional drawing explaining the deflection angle of the base tube part in the guide hole of a front cap. It is sectional drawing explaining the deflection angle of the base tube part in the guide hole of a back cap. (A), (B) is sectional drawing which expands and shows the sealing member accommodated in a seal | sticker accommodation recessed part. It is sectional drawing in the free state of a sealing member. It is sectional drawing which shows the holding | maintenance state by the valve storage hole of a front cap. It is sectional drawing which shows the conventional spray gun. It is sectional drawing which shows the structure of the air valve in another conventional spray gun.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spray gun 2 Gun body 3 Needle valve 3A Contact part 4 Paint discharge port 5 Paint flow path 6 Air discharge port 7 Air flow path 8 Air valve means 9 Trigger 16 Valve storage hole 20 Valve seat 21 Air valve 22 Front holding means 23 Rear holding means 24 Base tube portion 25 Valve portion 27 Front cap 27a Front guide holes 30, 35 Seal receiving recesses 30A, 35A Stepped surface portions 31, 34 Contact pieces 31o, 34o inside the seal members 31i, 34i Contact piece portions 31m, 34m Joint piece portion 33 Rear cap 33a Rear guide hole 41 Holding surface portion Hf Front air chamber Hr Rear air chamber

Claims (4)

A paint flow path having a paint discharge opening that is opened and closed by a needle valve, and an air discharge opening that atomizes and sprays the paint from the paint discharge opening by discharging air around the paint discharge opening. A spray gun having an air flow path, an air valve means for opening and closing the air flow path, and a trigger for sequentially operating the air valve means and the needle valve,
The air valve means includes
A valve housing hole formed in the gun body,
A valve seat that is mounted in the valve storage hole and divides the valve storage hole into front and rear air chambers;
An air valve having a base tube portion slidably inserted back and forth in the needle valve, and a valve portion swelled at an intermediate position in the longitudinal direction of the base tube portion and capable of opening and closing the valve seat;
A front holding means having a front cap provided with a guide hole for closing the front end of the front air chamber and guiding the air valve back and forth through the base tube portion;
And a rear holding means having a rear cap provided with a guide hole for closing the rear end of the rear air chamber and guiding the air valve back and forth through the base tube portion,
Each of the front and rear guide holes is a spray gun in which the base tube portion is loosely inserted with a play that can tilt at a swing angle θ of 1 ° or more with respect to the center line of each guide hole. . The front cap and the rear cap include a seal accommodating recess that is continuous with each guide hole via a step surface portion and has an inner peripheral surface portion that is larger in diameter and concentric than the guide hole,
And a radially inner contact piece that contacts the outer peripheral surface of the base tube portion and a radially outer contact that contacts the inner peripheral surface portion of the seal housing recess in the seal housing recess. An elastic seal member having a U-shaped cross-section composed of one piece and a joint piece extending along the stepped surface portion and between the inner and outer contact piece portions is accommodated, and the seal member is free before being accommodated. 2. The spray gun according to claim 1, wherein in the state, the inner and outer abutting pieces open into a C-shape toward the tip.   The valve housing hole has a holding surface portion that receives and holds the outer peripheral surface of the front cap at a front end portion thereof, and an inner diameter Di of the holding surface portion is less than an outer diameter Do of the outer peripheral surface of the front cap. The spray gun according to claim 1 or 2, wherein the front cap is held with play on the holding surface portion by being larger than 3 mm. The needle valve has a contact portion that contacts the rear end of the air valve at the rear end portion,
By the initial pulling of the trigger, the air valve is retracted to open the valve seat, and by further pulling, the air valve comes into contact with the contact portion of the needle valve, and the needle valve is integrated with the air valve. The spray gun according to any one of claims 1 to 3, wherein the paint discharge port is opened by retreating.

Images